Systems/methods of carrier aggregation

ABSTRACT

Various embodiments of carrier aggregation are provided that increase communications capacity and throughput. According to some embodiments, a transmitter is configured with a plurality of transmitter chains and, responsive to an aggregate bandwidth and/or frequency content of an overall signal that is to be transmitted by the transmitter, the overall signal is segmented into a plurality of components, each one of which comprises a bandwidth that is smaller than the bandwidth of the overall signal, and is thus transmitted by the plurality of transmitter chains of the transmitter. Accordingly, each component of the plurality of components of the overall signal is processed by a respective transmitter chain of the plurality of transmitter chains. Systems/methods of spatial multiplexing are also provided further increasing network capacity and throughput.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/767,537, filed Feb. 14, 2013, entitled Systems/Methods of CarrierAggregation Providing Increased Capacity Communications, which itself isa continuation of U.S. patent application Ser. No. 13/528,058, filedJun. 20, 2012, entitled Increased Capacity Communications for OFDM-BasedWireless Communications Systems/Methods/Devices, which itself is acontinuation of U.S. patent application Ser. No. 12/748,931, filed Mar.29, 2010, entitled Increased Capacity Communications for OFDM-BasedWireless Communications Systems/Methods/Devices, the disclosures of allof which are incorporated herein by reference in their entirety as ifset fully herein.

U.S. patent application Ser. No. 13/767,537 is also acontinuation-in-part of U.S. patent application Ser. No. 12/481,084,filed Jun. 9, 2009, entitled Increased Capacity Communications Systems,Methods and/or Devices, which itself claims the benefit of ProvisionalApplication Ser. No. 61/078,598, filed Jul. 7, 2008, entitled IncreasedCapacity Communications Systems, Devices and/or Methods; ProvisionalApplication Ser. No. 61/100,142, filed Sep. 25, 2008, entitledAdditional Systems, Devices and/or methods for Increasing Capacity ofCommunications Systems; Provisional Application Ser. No. 61/116,856,filed Nov. 21, 2008, entitled Further Systems, Devices and/or Methodsfor Increasing Capacity of Communications Systems; ProvisionalApplication Ser. No. 61/117,437, filed Nov. 24, 2008, entitledEqualizer-Based Increased Capacity OFDM Systems, Methods and Devices;Provisional Application Ser. No. 61/119,593, filed Dec. 3, 2008,entitled Equalizer-Based Increased Capacity OFDM Systems, Methods andDevices; Provisional Application Ser. No. 61/155,264, filed Feb. 25,2009 entitled Compact OFDM Systems, Devices and/or Methods; andProvisional Application Ser. No. 61/163,119, filed Mar. 25, 2009,entitled Additional Compact OFDM/OFDMA Systems, Devices and/or Methods,all of which are assigned to the assignee of the present invention, thedisclosures of all of which are hereby incorporated herein by referencein their entirety as if set forth fully herein.

U.S. patent application Ser. No. 13/767,537 is also acontinuation-in-part of U.S. patent application Ser. No. 12/978,092,filed Dec. 23, 2010, entitled Private, Covert and/or CognitiveCommunications Systems and/or Methods Based Upon Pseudo-RandomlyGenerated Communications Alphabets, which itself is a continuation ofU.S. patent application Ser. No. 12/620,057, filed Nov. 17, 2009,entitled Waveforms Comprising a Plurality of Elements and TransmissionThereof which itself is a continuation of U.S. application Ser. No.12/372,354, filed Feb. 17, 2009, entitled Wireless CommunicationsSystems and/or Methods Providing Low Interference, High Privacy and/orCognitive Flexibility, and claims priority to U.S. ProvisionalApplication No. 61/033,114, filed Mar. 3, 2008, entitled Next Generation(XG) Chipless Spread-Spectrum Communications (CSSC), and is acontinuation-in-part (CIP) of U.S. application Ser. No. 11/720,115,filed May 24, 2007, entitled Systems, Methods, Devices and/or ComputerProgram Products For Providing Communications Devoid of CyclostationaryFeatures, which is a 35 U.S.C. §371 national stage application of PCTApplication No. PCT/US2006/020417, filed on May 25, 2006, which claimspriority to U.S. Provisional Patent Application No. 60/692,932, filedJun. 22, 2005, entitled Communications Systems, Methods, Devices andComputer Program Products for Low Probability of Intercept (LPI), LowProbability of Detection (LPD) and/or Low Probability of Exploitation(LPE) of Communications Information, and also claims priority to U.S.Provisional Patent Application No. 60/698,247, filed Jul. 11, 2005,entitled Additional Communications Systems, Methods, Devices andComputer Program Products for Low Probability of Intercept (LPI), LowProbability of Detection (LPD) and/or Low Probability of Exploitation(LPE) of Communications Information and/or Minimum InterferenceCommunications, the disclosures of all of which are hereby incorporatedherein by reference in their entirety as if set forth fully herein. Theabove-referenced PCT International application was published in theEnglish language as International Publication No. WO 2007/001707.

BACKGROUND OF THE INVENTION

This invention relates to wireless and wireline communications systems,methods and/or devices and more particularly to wireless and wirelinecommunications systems, methods and/or devices that transmit/receiveinformation using an Orthogonal Frequency Division Multiplexed (“OFDM”)and/or Orthogonal Frequency Division Multiple Access (“OFDMA”) protocol.

In communications systems, wireline and/or wireless, a primary designobjective is to reduce or minimize noise and/or interference, whileincreasing or maximizing desired signal strength, in order to increaseor maximize system capacity. Much research has been conducted, andcontinues to be conducted, towards this objective. It is well known, forexample, that a communications receiver that is based upon “matchedfilter” principles is optimum in terms of maximally rejecting noisewhile maximally acquiring a desired signal. Further examples relate tothe many receiver and/or transmitter “equalization/cancellation”techniques that have been developed to combat effects of non-idealchannels and/or system devices that generate linear and/or non-linearInter-Symbol Interference (“ISI”), Adjacent Channel Interference (“ACI”)and/or Cross Polarization Interference (“CPI”).

At the current time, it appears that OFDM/OFDMA-based systems willproliferate as is evident by developments in the standardization anddeployment of OFDM/OFDMA-based systems, such as, for example, WiFi,WiMAX and LTE.

SUMMARY OF THE INVENTION

According to some embodiments of the present invention, a communicationsmethod is provided comprising: forming a data vector comprising N dataelements; N≧2; subjecting the data vector to a transformation andforming a transformed vector responsive to said subjecting; inserting atleast one pilot symbol into the transformed vector and forming anaugmented vector responsive to said inserting; and transmitting by atransmitter the augmented vector; wherein subjecting the data vector toa transformation occurs prior to said inserting and prior to saidforming an augmented vector; the transformation is based upon a Fouriertransform and/or a Butler matrix; and wherein transmitting by atransmitter comprises transmitting by the transmitter concurrently aplurality of N sub-carriers.

In some embodiments, the method may further comprise: prior to saidtransmitting by a transmitter, subjecting the augmented vector to afurther transformation that depends upon a characteristic of a channelthat exists between the transmitter and a receiver. In some embodiments,the Fourier transform may comprise a Discrete Fourier Transform (DFT)and/or a Fast Fourier Transform (FFT) and/or the Butler matrix may be atruncated Butler matrix; wherein the truncated Butler matrix may bebased upon one half of a conventional Butler matrix up to, but notincluding, a stage of the conventional Butler matrix where amplifiersexist.

In further embodiments of the invention, the method may furthercomprise: receiving at a receiver a time-domain version of the augmentedvector responsive to said transmitting by a transmitter the augmentedvector; Fourier transforming the time-domain version of the augmentedvector; forming an estimate of the transformed vector responsive to saidFourier transforming the time-domain version of the augmented vector;subjecting the estimate of the transformed vector to an inverse of thetransformation that the data vector has been subjected to; and formingan estimate of the data vector responsive to said subjecting theestimate of the transformed vector to an inverse of the transformation.

In additional embodiments, the method may further comprise: estimatingat the receiver, responsive to a processing of the at least one pilotsymbol by the receiver, a state of a communications channel throughwhich said receiving occurs; and providing data to the transmitterresponsive to said estimating.

In yet additional embodiments, the method may further comprise; forminga plurality of data vectors comprising data to be transmitted to arespective plurality of receivers; subjecting each one of the pluralityof data vectors to the transformation and forming a respective pluralityof transformed vectors responsive to said subjecting each one of theplurality of data vectors to the transformation; inserting at least onepilot symbol into each one of the respective plurality of transformedvectors thus forming a respective plurality of augmented vectors; andsequentially transmitting by the transmitter the respective plurality ofaugmented vectors to the respective plurality of receivers; whereinsequentially transmitting comprises sequentially transmitting andavoiding overlapping in time between any two of the respective pluralityof augmented vectors that are sequentially transmitted by thetransmitter.

In other embodiments the method/system provided may additionallycomprise: generating a number of replicas of the augmented vector;wherein the number of replicas is equal to, or is greater than, 2; andwherein each one of the number of replicas of the augmented vector isadjusted by dividing a magnitude thereof by the number of replicas thatare generated; transmitting by the transmitter the number of replicas ofthe augmented vector using a respective number of antenna elements; andprior to said transmitting by the transmitter to the receiver the numberof replicas of the augmented vector, subjecting each one of the numberof replicas of the augmented vector to a further transformation thatdepends upon a characteristic of a channel that exists between arespective antenna element, of the respective number of antennaelements, and the receiver, so that the number of replicas of theaugmented vector that are transmitted using the respective number ofantenna elements arrive at the receiver substantially in phase.

In some embodiments, receiving at a receiver comprises receiving at thereceiver using a spatial matched filter and/or a spatial rake; whereinreceiving at the receiver using a matched filter and/or a spatial rakecomprises: estimating at the receiver a number of signal paths arrivingat the receiver; estimating at the receiver a respective number ofchannel characteristics that is associated with the number of signalpaths arriving at the receiver; and forming at the receiver a respectivenumber of antenna lobes and/or spatial fingers responsive to saidestimating at the receiver a number of signal paths arriving at thereceiver and responsive to said estimating at the receiver a respectivenumber of channel characteristics that is associated with the number ofsignal paths arriving at the receiver.

According to embodiments of the invention, the estimating by thereceiver of a number of signal paths arriving at the receiver comprises:forming at the receiver an initial number of antenna lobes and/orspatial fingers; and processing at the receiver a respective initialnumber of signals that is provided by the initial number of antennalobes and/or spatial fingers that is formed; wherein the initial numberof lobes and/or spatial fingers that is formed at the receiver isgreater than the estimated number of signal paths arriving at thereceiver. In some embodiments, a combining at the receiver of arespective number of signals that are provided by the respective numberof antenna lobes and/or spatial fingers that are formed, is alsoprovided.

In yet further embodiments, the initial number of lobes and/or spatialfingers that is formed at the receiver spans a grid of two-dimensionalspace.

In order to reduce a complexity and/or a structural load, in someembodiments, receiving at a receiver further comprises: receiving at anantenna of the receiver that is situated at a distance from a processorof the receiver; amplifying following said receiving at an antenna ofthe receiver; wirelessly transmitting over a short-range link followingsaid amplifying; and receiving at the processor of the receiverresponsive to said wirelessly transmitting; wherein, in furtherembodiments, the antenna of the receiver comprises a two-dimensionallattice of antenna elements.

Embodiments relating to respective/corresponding systems, devices,software, firmware and/or computer programs/algorithms are alsopresented.

Some embodiments of the present invention provide for receiving a signalcomprising N first sub-carriers, wherein N≧2; generating 2N′ samples ofthe signal, wherein N′≧N; performing a first transformation on a firstsub-set of the 2N′ samples; performing a second transformation on asecond sub-set of the 2N′ samples; and combining an element of the firsttransformation with an element of the second transformation.

In some embodiments, the N first sub-carriers are orthogonaltherebetween.

In further embodiments of the invention, the signal further comprises Msecond sub-carriers; M≧0; wherein the M second sub-carriers aresuperimposed on the N first sub-carriers over a frequency interval ofbandwidth B Hz that is substantially occupied by the N firstsub-carriers and over a time interval of T seconds in duration overwhich the N first sub-carriers are defined. The M second sub-carriersmay be orthogonal therebetween and at least one of the M secondsub-carriers may not be orthogonal to at least one of the N firstsub-carriers.

The 2N′ samples may comprise 2N′ time-domain samples and at least one ofthe 2N′ time-domain samples may comprise a complex value. In someembodiments, the signal comprises a bandwidth of B Hz, wherein B≧NIT andwherein T denotes a signaling interval over which the N firstsub-carriers are defined.

In some embodiments of the invention, receiving a signal comprisesreceiving a passband signal wherein B is centered at a (carrier)frequency f₁ and wherein the passband signal is frequency shifted fromthe (carrier) frequency f₁ to a frequency f₂ prior to the generating 2N′samples of the signal. In accordance with some embodiments of theinvention, f₂=B/2, f₂=0, f₂<f₁ or f₂≧f₁.

Further to the above, a spacing between two adjacent sub-carriers of theN first sub-carriers may be 1/T Hz, a spacing between two adjacentsub-carriers of the M second sub-carriers may be 1/T Hz and a spacingbetween a first sub-carrier of the N first sub-carriers and asub-carrier of the M second sub-carriers that is adjacent to the firstsub-carrier of the N first sub-carriers may be ½T Hz.

In additional embodiments, the first sub-set of the 2N′ samplescomprises a first set of N″ samples and the second sub-set of the 2Nsamples comprises a second set of N′″ samples; wherein 1≦N″≦2N′ and1≦N′″≦2N′. In other embodiments, N″=N′″=N′, a spacing between twoadjacent samples of the first set of N″ samples is T/N′ seconds, aspacing between two adjacent samples of the second set of N′″ samples isT/N′ seconds and a spacing between a first sample of the first set of N″samples and a sample of the second set of N′″ samples that is adjacentto the first sample of the first set of N″ samples is T/2N′ seconds.

In some embodiments, the first transformation and the secondtransformation each comprises a time-domain to frequency-domaintransformation. The time-domain may be a discrete time-domain, thefrequency-domain may be a discrete frequency-domain and the time-domainto frequency-domain transformation may comprise a Discrete FourierTransform and/or a Fast Fourier Transform.

Some embodiments further comprise modifying the element of the firsttransformation and/or modifying the element of the second transformationprior to the combining. In some embodiments, combining comprises:forming γ^(T)b+δ^(T)r; wherein b comprises the element of the firsttransformation, r comprises the element of the second transformation,γ^(T)b comprises modifying the element of the first transformation,δ^(T)r comprises modifying the element of the second transformation andwherein the superscript T denotes vector (or matrix) transpose and/orconjugate transpose, as appropriate.

Yet further embodiments comprise calculating γ and δ such that astatistical expectation, such as, for example, E[|γ^(T)b+δ^(T)r−B_(k)|²]is minimized; wherein E[•] denotes statistical expectation, |•| denotesmagnitude and B_(k) denotes a data element that is associated with ak^(th) sub-carrier; k=1, 2, . . . , N. In some embodiments, calculatingcomprises calculating for at least one value of k; k=1, 2, . . . , N.Some embodiments further comprise using γ^(T)b+δ^(T)r to determine anestimate of B_(k) for at least one value of k, wherein γ and δ maydepend on k.

Further to the above, communicating information may be provided byforming a first Orthogonal Frequency Division Multiplexed (“OFDM”)and/or a first Orthogonal Frequency Division Multiple Access (“OFDMA”)carrier comprising a first number of sub-carriers that are orthogonaltherebetween; forming a second OFDM and/or OFDMA carrier comprising asecond number of subcarriers that are orthogonal therebetween but maynot be orthogonal to the first number of sub-carriers; superimposing intime and in frequency, the first OFDM/OFDMA carrier with secondOFDM/OFDMA carrier such as to generate a level of interferencetherebetween, that may be substantial interference therebetween; andtransmitting the superimposed first and second OFDM/OFDMA carriers.Analogous methods, systems and/or devices may also be provided.

Further embodiments of systems and/or devices may be provided accordingto the present invention. For example, a communications receiver may beprovided comprising a processor that is configured to: receive a signalcomprising N first sub-carriers, wherein N≧2; generate 2N′ samples ofthe signal, wherein N′≧N; perform a first transformation on a firstsub-set of the 2N′ samples; perform a second transformation on a secondsub-set of the 2N′ samples; and combine an element of the firsttransformation with an element of the second transformation.

Additional methods/systems/devices may be provided according toadditional embodiments of the present invention wherein first and secondportions of an OFDM carrier are formed by a transmitter, via respectivefirst and second operations. The first and second operations may befirst and second Discrete Fourier Transforms (“DFTs”), Fast FourierTransforms (“FFTs”), Inverse Discrete Fourier Transforms (“IDFTs”)and/or Inverse Fast Fourier Transforms (“IFFTs”).

The first and second portions of the OFDM carrier may be kept separate,may be amplified by respective different/separate first and second poweramplifiers of the transmitter and may then be combined/superimposed,after high-power amplification, prior to transmission over a propagationmedium. In other embodiments, the first and second portions of the OFDMcarrier are kept separate even after the amplification (are notcombined) and are used to excite respective first and seconddifferent/separate propagation media and/or channels, such as, forexample, first and second different wireline propagation media(different first and second twisted-pair, different first and secondcoaxial cables and/or different first and second fiber-opticalpropagation media, etc.) and/or different first and second wirelesspropagation media via respective first and second antennas (or antennaelements).

Some embodiments of the invention provide a communications methodcomprising:

forming a plurality of components of an overall signal that is to betransmitted by a transmitter such that each one of the plurality ofcomponents comprises a characteristic value that is less than acorresponding characteristic value associated with the overall signal;

configuring the transmitter with a plurality of elements correspondingto the plurality of components of the overall signal; and

transmitting the overall signal by transmitting by the transmitter theplurality of components of the overall signal by using the correspondingplurality of elements.

According to further embodiments of the invention the method provides arecognition of exceeding by the overall signal that is to be transmittedby the transmitter a limit associated with a subsystem of thetransmitter;

avoiding said exceeding by refraining from transmitting the overallsignal via said subsystem of the transmitter; and

transmitting the plurality of components of the overall signal via thecorresponding plurality of elements of the transmitter, thustransmitting the overall signal; wherein according to some embodiments,the limit is a bandwidth limit.

In some embodiments, the subsystem of the transmitter comprises anantenna of the transmitter and/or an element of the transmitter otherthan the antenna.

In further embodiments, said overall signal comprises first and secondfrequency segments that are separated therebetween by a substantialfrequency interval over which the overall signal is substantially devoidof frequency content; wherein in some embodiments, the first and secondfrequency segments comprise an aggregate bandwidth of 100 MHz; the firstfrequency segment comprises a bandwidth of 40 MHz; and the secondfrequency segment comprises a bandwidth of 60 MHz,

According to yet additional embodiments, said characteristic valuecomprises a bandwidth, a number of points of a Discrete FourierTransform and/or a number of points of an Inverse Discrete Fouriertransform.

In further embodiments, said plurality of components of the overallsignal comprises first and second components and wherein said pluralityof elements corresponding to the plurality of components comprises firstand second elements; wherein, according to some embodiments, the firstand second elements comprise first and second antennas, first and secondpower amplifiers, first and second Discrete Fourier Transforms and/orfirst and second Inverse Discrete Fourier transforms.

According to additional embodiments of the method, said configuring thetransmitter with a plurality of elements corresponding to the pluralityof components of the overall signal comprises:

configuring the transmitter with the first and second antennas, thefirst and second power amplifiers, the first and second Discrete FourierTransforms and/or the first and second Inverse Discrete Fouriertransforms; and

wherein said transmitting the overall signal by transmitting by thetransmitter the plurality of components of the overall signal by usingthe corresponding plurality of elements comprises:

transmitting the first component by using the first antenna, the firstpower amplifier, the first Discrete Fourier transform and/or the firstInverse Discrete Fourier Transform; and

transmitting the second component by using the second antenna, thesecond power amplifier, the second Discrete Fourier transform and/or thesecond Inverse Discrete Fourier Transform,

Further embodiments of the method provide:

receiving information by the transmitter from a receiver;

forming a matrix by the transmitter responsive to said receivinginformation; and

processing the plurality of components by using the matrix prior totransmitting the plurality of components by the transmitter; wherein,according to some embodiments, receiving information comprises receivingchannel information; forming a matrix comprises forming the matrix as aproduct of first and second matrices responsive to receiving the channelinformation; and wherein said processing the plurality of components byusing the matrix comprises multiplying the plurality of components bythe matrix.

In yet additional embodiments of the invention, the method furtherprovides:

receiving information by the transmitter from first and secondreceivers;

forming first and second matrices by the transmitter responsive to saidreceiving information by the transmitter from the first and secondreceivers;

processing a first plurality of components by using the first matrixprior to transmitting the first plurality of components by thetransmitter; and

processing a second plurality of components by using the second matrixprior to transmitting the second plurality of components by thetransmitter.

The invention also provides a communications system comprising:

a processor that is configured to form a plurality of components of anoverall signal that is to be transmitted such that each one of theplurality of components comprises a characteristic value that is lessthan a corresponding characteristic value associated with the overallsignal; and

a transmitter that is configured with a plurality of elementscorresponding to the plurality of components of the overall signal andis further configured to transmit the overall signal by transmitting theplurality of components of the overall signal by using the correspondingplurality of elements.

In some embodiments, the processor is further configured to:

recognize that the overall signal that is to be transmitted will exceeda limit associated with a subsystem of the transmitter;

prevent the limit from being exceeded by refraining from sending theoverall signal to said subsystem of the transmitter;

form the plurality of components of the overall signal; and

send the plurality of components to the transmitter to be transmittedtherefrom via the corresponding plurality of elements of thetransmitter, thus transmitting the overall signal; wherein, according tosome embodiments, the limit is a bandwidth limit.

According to some embodiments, the subsystem of the transmittercomprises an antenna of the transmitter and/or an element of thetransmitter other than the antenna.

In other embodiments, said overall signal comprises first and secondfrequency segments that are separated therebetween by a substantialfrequency interval over which the overall signal is substantially devoidof frequency content; wherein, according to some embodiments, the firstand second frequency segments comprise an aggregate bandwidth of 100MHz; the first frequency segment comprises a bandwidth of 40 MHz; andthe second frequency segment comprises a bandwidth of 60 MHz.

According to further embodiments, said characteristic value comprises abandwidth, a number of points of a Discrete Fourier Transform and/or anumber of points of an Inverse Discrete Fourier transform.

In yet other embodiments, said plurality of components of the overallsignal comprises first and second components and wherein said pluralityof elements corresponding to the plurality of components comprises firstand second elements; wherein, according to some embodiments, the firstand second elements comprise first and second antennas, first and secondpower amplifiers, first and second Discrete Fourier Transforms and/orfirst and second Inverse Discrete Fourier transforms.

In further embodiments of the invention, the transmitter is configuredwith the first and second antennas, the first and second poweramplifiers, the first and second Discrete Fourier Transforms and/or thefirst and second Inverse Discrete Fourier transforms; and

wherein the transmitter is further configured to transmit the firstcomponent by using the first antenna, the first power amplifier, thefirst Discrete Fourier transform and/or the first Inverse DiscreteFourier Transform; and to transmit the second component by using thesecond antenna, the second power amplifier, the second Discrete Fouriertransform and/or the second Inverse Discrete Fourier Transform.

According to additional embodiments of the invention, the transmitter isfurther configured to:

receive information from a receiver;

form a matrix responsive to the received information; and

process the plurality of components by using the matrix prior totransmitting the plurality of components; wherein, according to someembodiments, said information comprises channel information; said matrixcomprises a product of first and second matrices; and wherein thetransmitter is configured to multiply the plurality of components bysaid matrix.

In yet additional embodiments according to the invention, thetransmitter is further configured to:

receive information from first and second receivers;

form first and second matrices responsive to having received saidinformation from the first and second receivers;

process a first plurality of components by using the first matrix priorto transmitting the first plurality of components; and

process a second plurality of components by using the second matrixprior to transmitting the second plurality of components.

Numerous embodiments of systems/methods relating to space divisionmultiplexing may also be provided. For example, according to somesystems embodiments of the invention, the transmitter may further beconfigured to:

transmit first and second signals, to respective first and secondreceivers, substantially simultaneously therebetween, substantiallyco-frequency therebetween and devoid of any reliance on any codediscrimination therebetween, responsive to a first orientation betweenthe first and second receivers; and

transmit the first and second signals, to the respective first andsecond receivers, substantially simultaneously therebetween whilerelying on frequency discrimination and/or code discriminationtherebetween, responsive to a second orientation between the first andsecond receivers;

wherein the first orientation between the first and second receiversallows an antenna of the transmitter to form respective first and secondantenna patterns that provide a first level of antenna patterndiscrimination therebetween; and

wherein the second orientation between the first and second receiversallows an antenna of the transmitter to form respective first and secondantenna patterns that provide a second level of antenna patterndiscrimination therebetween that is less than the first level of antennapattern discrimination.

Methods embodiments that are analogous to the above may also beprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a superposition of first and second OFDM/OFDMAcarriers according to various embodiments of the invention, whereN=number of orthogonal OFDM solid subcarriers, ξ=excess bandwidth factorto accommodate sidelobes of subcarriers (ξ≧0) and T=signaling interval(only the main lobes of the subcarriers are illustrated).

FIG. 2 provides Bit Error Rate (“BER”) curves according to embodimentsof the invention.

FIG. 3 provides further BER curves according to further embodiments ofthe invention.

FIG. 4 a illustrates systems/methods/devices of return-linkcommunications according to embodiments of the invention that use aspatial discrimination between two or more receiver/transmitterantennas.

FIG. 4 b provides BER curves that are associated with methods, systemsand/or devices that are based upon FIG. 4 a; Return Link—BER for theblack or the red signals with antenna spatial isolation between the two(N=256, QPSK/QPSK)

FIG. 5 a illustrates systems/methods/devices of forward-linkcommunications according to embodiments of the invention that use aspatial discrimination between two or more receiver/transmitterantennas.

FIG. 5 b provides BER curves that are associated with methods, systemsand/or devices that are based upon FIG. 5 a; Forward Link—BER for theblack signal with antenna spatial isolation between the black and thered (N=256, QPSK/QPSK).

FIG. 6 illustrates methods/systems/devices according to embodiments ofthe invention.

FIG. 7 illustrates methods/systems/devices according to embodiments ofthe invention.

FIGS. 8, 9, 10 and 11 illustrate receiver methods/systems/devicesaccording to various embodiments of the invention.

FIG. 12 illustrates a transformation that may be imposed on a datavector by a transmitter, prior to the transmitter transmitting the datavector, in order to distribute elements of the data vector over anavailable space (frequency space) and/or provide diversity/robustnessagainst channel impairments such as fading and/or interference.

FIG. 13 illustrates functions of a receiver according to embodiments ofthe invention.

FIG. 14 illustrates functions of a transmitter that is communicatingsequentially in time with a plurality of transceivers.

FIG. 15 a illustrates functions of a base station according toembodiments of the invention.

FIG. 15 b illustrates functions of a base station according to furtherembodiments of the invention.

FIG. 16 illustrates functions of and/or coordination between clusters ofproximate base stations according to embodiments of the invention.

FIG. 17 illustrates a plurality of antennas transmitting a respectiveplurality of signals (a respective plurality of replicas of a signalvector B) appropriately compensated for a respective plurality ofchannel characteristics, in order to provide substantial voltageaddition at an antenna element of a receiver.

FIG. 18 a illustrates a function of a spatial rake receiver and/or aspatial matched filter receiver according to embodiments of theinvention.

FIG. 18 b illustrates further functions/characteristics of a spatialrake receiver and/or a spatial matched filter receiver according toembodiments of the invention.

FIG. 19 a illustrates functions of a receiver that is configured to forma spatial rake and/or a spatial matched filter according to embodimentsof the invention.

FIG. 19 b illustrates further functions of a receiver that is configuredto form a spatial rake and/or a spatial matched filter according toembodiments of the invention.

FIG. 20 illustrates yet additional functions of a receiver that isconfigured to form a spatial rake and/or a spatial matched filter andmay further be configured to provide equalization, rake receiverprocessing in a time domain and/or interference reduction, in aco-channel communications environment (including intra-system co-channelinterference and/or inter-system co-channel interference) according toembodiments of the invention; Receiver providing co-channelcommunications to two terminals concurrently using spatial matchedfiltering (antenna beam forming), equalizer/rake and/or an interferencereducer.

FIG. 21 further illustrates functions/characteristics of atransmitter/receiver that is configured to form/provide a spatial rakeand/or a spatial matched filter according to embodiments of theinvention.

FIG. 22 illustrates an electrical/mechanical architecture of a basestation according to embodiments of the invention.

FIG. 23 further illustrates the electrical/mechanical architecture ofthe base station of FIG. 22 according to embodiments of the invention.

FIG. 24 illustrates a substantially cylindrical electrical/mechanicalarchitecture of a base station comprising a two-dimensional lattice ofantenna elements, according to additional embodiments of the invention.

FIG. 25 further illustrates a top view of an electrical/mechanicalarchitecture of a base station according to yet additional embodimentsof the invention.

DETAILED DESCRIPTION

The present application hereby incorporates herein by reference thedisclosures of all of the following applications in their entirety as ifset forth fully herein: U.S. patent application Ser. No. 12/481,084,filed Jun. 9, 2009, entitled Increased Capacity Communications Systems,Methods and/or Devices, which claims the benefit of ProvisionalApplication Ser. No. 61/078,598, entitled Increased CapacityCommunications Systems, Devices and/or Methods, filed Jul. 7, 2008;Provisional Application Ser. No. 61/100,142, entitled AdditionalSystems, Devices and/or Methods for Increasing Capacity ofCommunications Systems, filed Sep. 25, 2008; Provisional ApplicationSer. No. 61/116,856, entitled Further Systems, Devices and/or Methodsfor Increasing Capacity of Communications Systems, filed Nov. 21, 2008;Provisional Application Ser. No. 61/117,437, entitled Equalizer-BasedIncreased Capacity OFDM Systems, Methods and Devices, filed Nov. 24,2008; Provisional Application Ser. No. 61/119,593, entitledEqualizer-Based Increased Capacity OFDM Systems, Methods and Devices,filed Dec. 3, 2008; Provisional Application Ser. No. 61/155,264,entitled Compact OFDM Systems, Devices and/or Methods, filed Feb. 25,2009; and Provisional Application Ser. No. 61/163,119, entitledAdditional Compact OFDM/OFDMA Systems, Devices and/or Methods, filedMar. 25, 2009, all of which are assigned to the assignee of the presentinvention.

The present invention now will be described with reference to theaccompanying drawings. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided tofurther convey the scope of the invention to those skilled in the art.It will be understood that any two or more embodiments of the presentinvention may be combined in whole or in part to form at least one ormore additional embodiments.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. Furthermore, “connected” or “coupled” as used herein mayinclude wirelessly connected or coupled.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless expressly stated otherwise. Itwill be further understood that the terms “includes,” “comprises,”“including” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

It will be understood that although terms such as first and second areused herein to describe various elements, these elements should not belimited by these terms. These terms are only used to distinguish oneelement from another element. Thus, a first element below could betermed a second element, and similarly, a second element may be termed afirst element without departing from the teachings of the presentinvention. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. The symbol“/” is also used as a shorthand notation for “and/or”. Moreover, as usedherein, the term “subset” shall be interpreted to mean a set (a firstset) that contains at least one but less than all members/elements ofanother set (a second set). That is, if S is a subset of SS, then Scontains at least one but less than all elements of SS. Morespecifically, if, for example, SS={s₁, s₂, s₃, s₄, s₅}, then S={s₂}, forexample, is a subset of SS. Also, S={s₁, s₃, s₅} is a subset of SS, etc.

As used herein, the term “transmitter” and/or “receiver” include(s)transmitters/receivers of cellular and/or satellite terminals with orwithout a multi-line display; Personal Communications System (“PCS”)terminals that may include data processing, facsimile and/or datacommunications capabilities; Personal Digital Assistants (“PDA”) thatcan include a radio frequency transceiver and/or a pager,Internet/Intranet access, Web browser, organizer, calendar and/or aGlobal Positioning System (“GPS”) receiver; and/or conventional laptopand/or palmtop computers or other appliances, which include a radiofrequency transceiver. As used herein, the term “transmitter” and/or“receiver” also include(s) any other radiating and/or receiving device,equipment and/or source that may have time-varying and/or fixedgeographic coordinates and/or may be portable, transportable, installedin a vehicle (aeronautical, maritime, or land-based) and/orsituated/configured to operate locally and/or in a distributed fashionin one or more vehicles (land-mobile, maritime and/or aeronautical). Atransmitter and/or receiver also may be referred to herein as a“terminal,” “wireless terminal,” “mobile device,” “radioterminal,”“radiotelephone,” “base transceiver station,” “base station,” “accesspoint,” and/or “end-user device.” In addition, it will be understoodthat a transmitter and/or receiver may be configured to operate in awireless and/or a wired (wireline, cable, fiber, etc.) mode.

Various embodiments of the present invention are based upon therealization that a time-domain to frequency-domain transformation, suchas, for example, a Discrete Fourier Transform (“DFT”) and/or a FastFourier Transform (“FFT”), provides information that is associated witha specific number of frequency-domain points only. For example, anN-point FFT provides information that is associated with precisely Nfrequency-domain points on a frequency axis; wherein N may be equal to,for example, 2, 4, 8, 16, 32, 64, etc. There may be, however,information that is associated with additional frequency-domain pointson the frequency axis, other than the N-points. The information that isassociated with the additional frequency-domain points on the frequencyaxis, other than the N-points, may include what may be termed“interference,” but even interference contains energy that may be usefulenergy, and this interference may lend itself tomitigation/equalization, particularly when a processor is configured tooperate on the interference and on other signals that have given rise toand/or are related to the interference. Accordingly, a communicationsreceiver may be configured to observe information associated with, forexample, a received Orthogonal Frequency Division Multiplexed (“OFDM”)carrier, comprising N sub-carriers, by subjecting a time-domainrepresentation of the received OFDM carrier to an N-point FFT, as isconventionally done, providing an N-dimensional vector of values that isassociated with an N-dimensional data vector that is associated with theN sub-carriers of the OFDM carrier.

The time-domain representation of the received OFDM carrier, however,may additionally be subjected to a second N-point FFT (or to a secondM-point FFT, wherein M may be greater than, or less than, N) to providefrequency-domain information associated with, for example, N (or M)“transition,” “interstitial” or “in-between” frequencies on thefrequency axis. The transition, interstitial or in-between frequenciesmay be selected/located (on the frequency axis) between orthogonallydisposed OFDM sub-carriers. Accordingly, the second FFT may provideinformation containing interference from a plurality of side-lobes ofthe orthogonally disposed OFDM sub-carriers. However, informationcontaining interference may still be valuable. Just like in time-domainequalization, information containing interference, such as, for example,Inter-Symbol Interference (“ISI”), may be used advantageously to improvecommunications performance, frequency-domain information, even though itmay contain interference, such as, for example, frequency-domain ISI,may also be used advantageously to improve communications performance.

According to embodiments of the present invention, first and secondsignals may be transmitted by a transmitter. The first signal may bereferred to herein as the blue, black and/or solid signal, whereas thesecond signal may be referred to herein as the red and/or dotted signal.In some embodiments, the first and second signals represent respectivefirst and second OFDM/OFDMA carriers, wherein each one of the first andsecond OFDM/OFDMA carriers may comprise a plurality of subcarriers, asis illustrated in FIG. 1. (It will be understood that in FIG. 1 eventhough only three subcarriers are pointed to as being “dotted” and“solid,” respectively, this is done to minimize clutter in the Figure.All subcarriers that are drawn in solid traces may belong to the “solid”signal and all subcarriers that are drawn in dotted traces may belong tothe “dotted” signal.) The first OFDM/OFDMA carrier may comprise a firstnumber, N, of subcarriers that may be orthogonal therebetween (i.e., anytwo different subcarriers of the first number N of subcarriers may beorthogonal therebetween over a T-seconds signaling interval) and thesecond OFDM/OFDMA carrier may comprise a second number, M, ofsubcarriers that may be orthogonal therebetween (i.e., any two differentsubcarriers of the second number M of subcarriers may be orthogonaltherebetween over the T-seconds signaling interval, as is illustrated inFIG. 1 herein, or over a signaling interval that is different than theT-seconds signaling interval, as is illustrated in FIG. 1 of ProvisionalApplication Ser. No. 61/078,598, entitled Increased CapacityCommunications Systems, Devices and/or Methods, filed Jul. 7, 2008, andincorporated herein by reference in its entirety as if set forth fullyherein) wherein M may be equal to N, in some embodiments, or M may bedifferent from N in other embodiments. The first number N of subcarriersmay not be orthogonal to the second number M of subcarriers as isillustrated in FIG. 1 herein and/or in FIG. 1 of the above citedProvisional application (i.e., a subcarrier of the first number N ofsubcarriers may not be orthogonal to a subcarrier of the second number Mof subcarriers). In yet other embodiments, the first and/or secondsignal may represent a signal that is not based upon OFDM/OFDMA; suchas, for example, a Nyquist signal or a half-Nyquist signal.

It will be understood that at least one subcarrier of the second numberM of subcarriers may be a subcarrier comprising pilot information andthat, in some embodiments, each one of the second number M ofsubcarriers may be a subcarrier comprising pilot information.Accordingly, in such embodiments, the first signal, comprising the firstnumber N of subcarriers, may be relieved from providing pilotinformation and may thus be configured to provide additional data, thusincreasing a capacity measure thereof (i.e., a capacity measure of theblue, black and/or solid signal). In such embodiments, a receiver may beconfigured to use a priori pilot-related knowledge in order to mitigateinterference from the second signal into the first signal, to determinedata associated with the first signal, to use the data associated withthe first signal that is determined to mitigate interference from thepilots, to further process the pilots to determine channel-relatedinformation and to use the channel-related information that isdetermined to determine additional data of the first signal over a nextsignaling interval. According to some embodiments, a number of pilotsthat is included in the second number M of subcarriers (i.e., in thedotted/red signal) over said next signaling interval is reduced relativeto a number of pilots that is included in the second number M ofsubcarriers prior to said next signaling interval. Accordingly, in suchembodiments, the second number M of subcarriers may comprise additionaldata over said next signaling interval compared to a datacontent/measure thereof over a signaling interval prior to said nextsignaling interval. The data may be of the type/mode R=B, as is furtherdescribed below. In some embodiments, the channel-related informationthat is determined is used by the receiver and/or is sent by thereceiver to a transmitter to be used by the transmitter in transmitting(e.g., pre-distorting) the first signal and/or the second signal. Thetransmitter may use the channel-related information to pre-distort (atleast partially) the first signal and/or the second signal prior totransmission thereof. The second number M of subcarriers (i.e., thedotted/red signal) may be transmitted by the transmitter over apolarization that is different than, and, in some embodiments, issubstantially orthogonal to, a polarization used by the transmitter totransmit the solid signal.

Responsive to the first and second signals having been transmitted by atransmitter, a receiver may be configured to process respective firstand second signals that, according to some embodiments of the presentinvention, may represent respective first and second frequency-domainsignals (or frequency-domain observables), that may be expressed asb=B+āR+n and r=R+ūB+ν, respectively. The first and secondfrequency-domain observables comprise respective desired signalcomponents, B and R, respective components reflecting interference, āRand ūB, and respective components reflecting noise, n and ν. Thequantities b, r, B, R, n and ν may represent vector quantities and thequantities ā and ū may represent matrix quantities. A signal processorof the receiver may be configured to process the first and/or secondfrequency-domain observables to determine information (data) associatedwith the first and/or second transmitted signals.

In some embodiments according to the present invention, a receiver maybe configured to acquire a minimum of 2N time-domain samples of areceived OFDM/OFDMA signal over a signaling interval, “T,” thereof (orover an integer multiple of the signaling interval T; wherein N denotesan FFT/DFT size and/or a number of subcarriers associated with theOFDM/OFDMA signal) and using a first subset of the 2N time-domainsamples, that may be a subset comprising N first samples of the 2Ntime-domain samples, wherein, for example, the N first samples compriseeven indexed samples, of the 2N time-domain samples, to form a firstFFT/DFT (a conventional FFT/DFT at frequencies k/T); and using a secondsubset of the 2N time-domain samples, that may be a subset comprising Nsecond samples of the 2N time-domain samples, wherein, for example, theN second samples comprise odd indexed samples, of the 2N time-domainsamples, to form a second FFT/DFT at the “in-between” (i.e., at theinterstitial or transition) frequencies of (2k+1)/2T (k+½)/T; k=1, 2, .. . , N; wherein T denotes the signaling interval. The first FFT/DFT maybe used to provide a first N-dimensional vector “b” while the secondFFT/DFT may be used to provide a second vector “r,” that may be a secondN-dimensional vector r. The two vectors, b and r, may then be combinedin, for example, a least mean-squared-error sense. It will be understoodthat, in some embodiments, instead of using the even indexed samplesdiscussed above to form/define b, the odd indexed samples may be used,and instead of using the odd indexed samples discussed above toform/define r, the even indexed samples may be used. Othercombinations/subsets of the minimum 2N time-domain samples may also beused, in further embodiments, to form/define b and r.

In other embodiments of the present invention, instead of the above orin combination with the above, a 2N-point DFT/FFT may be performed onthe 2N time-domain samples and a first subset of points of the 2N-pointDFT/FFT, that may be a first subset of N points of the 2N-point DFT/FFT,comprising, for example, a subset of N even indexed points of the2N-point DFT/FFT, may be used to define the vector b while a secondsubset of points of the 2N-point DFT/FFT, that may be a second subset ofN points of the 2N-point DFT/FFT, comprising, for example, a subset of Nodd indexed points of the 2N-point DFT/FFT, may be used to define thevector r. It will be understood that, in some embodiments, instead ofusing the even indexed samples/points discussed above to form/define b,the odd indexed samples/points may be used, and instead of using the oddindexed samples/points discussed above to form/define r, the evenindexed samples/points may be used. Other sample/point combinations mayalso be used, in further embodiments, to form/define b and r.

In some embodiments of the invention, prior to acquiring the minimum of2N time-domain samples discussed above, a received passband OFDM/OFDMAcarrier, whose frequency content and/or whose allocated frequencychannel may be centered at a frequency f_(c), may be shifted down (i.e.,translated in frequency) not by f_(c) (as is conventionally done) butinstead, may be shifted down by f_(c)−N/2T (or by any other value). Thismay be necessary, in some embodiments, to provide uncorrelated and/orindependent noise vectors n and ν.

In some embodiments of the present invention, a signal processor may beconfigured to jointly process the first and second frequency domainobservables b, r. In other embodiments, the signal processor may beconfigured to perform first and second signal processing operationssequentially (e.g., over respective first and second substantiallynon-overlapping time intervals or over respective first and second timeintervals that overlap therebetween at least partially) in order todetermine information (data) associated with the first and/or secondtransmitted signal vectors B, R.

The signal processor may be configured to form, for example, γ^(T)b andδ^(T)r and to combine γ^(T)b with δ^(T)r to form γ^(T)b+δ^(T)r; whereinthe superscript T denotes vector transpose (or matrix transpose) orconjugate transpose, as appropriate, and wherein γ and δ may, accordingto some embodiments, denote vector quantities that may becomplex-valued. The signal processor may be configured to calculate γand δ such that a statistical expectation, for example,E[|γ^(T)b+δ^(T)r−B_(k)|²], is minimized; wherein E[•] denotesstatistical expectation, |•| denotes magnitude and B_(k) denotes a dataelement (complex, imaginary or real-valued) that is associated with ak^(th) sub-carrier that may represent a k^(th) element of B; k=1, 2, . .. , N.

In some embodiments of the present invention, the signal processor maybe configured to reduce and/or minimize (or substantially reduce and/orminimize) a mean-squared error quantity, performance index and/or costfunction wherein the first and second transmitted signal vectors, B, R,are substantially independent therebetween (this may be referred toherein as “Case 1”).

In some embodiments relating to Case 1, the values of γ and δ thatminimize E[|γ^(T)b+δ^(T)r−B_(k)|²] may satisfy the following equations:

Āγ+Ēδ=1_(k); and

Ōγ+Ūδ=ū1_(k);

wherein

Ā=(σ_(R) ²/σ_(B) ²)āā^(T)+(1+σ_(n) ²/σ_(B) ²)Ī;

Ē=ū^(T)+(σ_(R) ²/σ_(B) ²)ā;

Ō=ū+(σ_(R) ²/σ_(B) ²)ā^(T); and

Ū=ūū^(T)+(σ_(R) ²/σ_(B) ²+σ_(ν) ²/σ_(B) ²)Ī;

In the above equations, 1_(k) denotes a column vector that includes allzero entries except for the k^(th) entry thereof which is unity, and allquantities with a bar on top and a bar below represent matrices whoseelements may be complex-valued, real, and/or imaginary. Further to theabove, elements of the matrix ū represent levels of interference(leakage) from the blue sub-carriers, B, to the red sub-carriers R, Īdenotes an identity matrix, σ_(n) ² denotes variance of acomponent/element of n, σ_(R) ² denotes variance of a component/elementof R, σ_(B) ² denotes variance of a component/element of B, elements ofthe matrix ā represent levels of interference (leakage) from the redsub-carriers, R, to the blue sub-carriers B; and σ_(ν) ² denotesvariance of a component/element of ν.

It will be understood that when the symbol “T” is used as a superscript,it will be interpreted to denote vector transpose, matrix transposeand/or conjugate transpose (of a vector or a matrix, as appropriate),not only in the above equations but throughout this specification,unless otherwise specified. It will further be understood that thesymbol “T” may also be used to denote a time interval (e.g., a signalinginterval) when it is not used as a superscript. Unless otherwisespecified, when “T” is used in any way other than a superscript, it willbe interpreted to represent a time interval.

In deriving the above equations, the quantities B, R, n and ν may beassumed to be statistically independent therebetween and each one of thequantities B, R, n and ν may be assumed to be of zero mean. In otherembodiments, however, a statistical dependence (a non-zero correlationand/or non-zero covariance matrix) may be assumed between any two of thestated vector quantities and equations corresponding to such assumptionsmay be derived, as those skilled in the art will appreciate.

In other embodiments of the present invention, a signal processor may beconfigured to reduce and/or minimize (or substantially reduce and/orminimize) a mean-squared error quantity, performance index and/or costfunction wherein the first and second transmitted signal vectors B, Rare substantially dependent therebetween (this may be referred to hereinas “Case 2”). In some embodiments, the first and second transmittedsignal vectors (B, R) may comprise substantially identical information(data) therebetween (e.g., B=R). Computer simulation results associatedwith Case 2, wherein B=R, show that a channel capacity measure may beincreased by 100% in some embodiments of the invention, and by 50% inother embodiments of the invention, as is illustrated in FIG. 2. Thismay be a significant finding.

In some embodiments relating to Case 2, the values of γ and δ thatminimize E[|γ^(T)b+δ^(T)r−B_(k)|²] may satisfy the following equations:

Ā′γ+Ē′δ=ā′1_(k); and

Ō′γ+Ū′δ=ū′1_(k);

wherein

Ā′=ā′(ā′)^(T)+(σ_(n) ²/σ_(B) ²) Ī;

Ē′=ā(ū′)^(T);

Ō′=ū′(ā′)^(T); and

Ū′=ū′(ū′)^(T)+(σ_(ν) ²/σ_(B) ²)Ī;

wherein, as before, 1_(k) denotes a column vector with all zero entriesexcept for the k^(th) entry thereof which is unity, and all quantitieswith a bar on top and a bar below represent matrices whose elements maybe complex-valued, real-valued and/or imaginary-valued. Furthermore,ā′=Ī+ā and ū′=Ī+ū; wherein ā and ū are as defined above relative to Case1 with the elements of matrix ā representing levels of interference(i.e., leakage) from the red sub-carriers, R, to the blue sub-carriers,and with the elements of the matrix ū representing levels ofinterference (leakage) from the blue sub-carriers, B, to the redsub-carriers. Also, as defined earlier in connection with Case 1 above,σ_(n) ² denotes variance of a component of n, σ_(ν) ² denotes varianceof a component of ν, σ_(B) ² denotes variance of a component of B and Īdenotes an identity matrix. In deriving the above equations, B, n and νhave been assumed to be statistically independent therebetween and eachof zero mean. In other embodiments, however, a statistical dependence (anon-zero correlation and/or non-zero covariance matrix) may be assumedbetween any two of the stated vector quantities and equationscorresponding to such assumptions may be derived, as those skilled inthe art will appreciate.

It may be observed that in embodiments relating to Case 2, the signalprocessor may be viewed as performing voltage addition of first andsecond signals received, responsive to the first and second signals thatare transmitted comprising the substantially identical (e.g., B=R)information (data) therebetween. It may also be observed that inaccordance with embodiments relating to Case 2, the signal processor maybe viewed as providing increased desired signal power/energy by makinguse (and taking advantage) of signal samples at frequencies thatconventional receivers neglect. Upon reflection, an analogy may be drawnbetween the signal processor described herein with respect to Case 2(and Case 3, as discussed below herein) and a time-domain equalizer or atime-domain rake receiver. As is the case with a time-domain equalizerand/or a time-domain rake receiver, coherently combining desired signalcomponents that are dispersed in time, the signal processor used hereincombines coherently desired signal components that may be viewed asbeing dispersed in frequency.

In some embodiments of the present invention that are associated withwhat may be referred to herein as Case 3, only one of the first andsecond signals (B, R) is transmitted (for example, only B istransmitted) and a receiver processor may be configured, in someembodiments, substantially as in Case 1 with R→0, (i.e., with eachelement/component of the vector R set to zero) to process the receiverobservables that, in some embodiments, may be b=B+n and r=ūB+ν. Computersimulation results associated with Case 3 (see FIG. 3), show that apower efficiency measure (e.g., E_(b)/N₀) may improve by up to 3 dB overthat provided by conventional OFDM/OFDMA systems, devices and/ormethods.

As stated earlier, and as may be appreciated by those skilled in theart, according to various embodiments of the present invention, thereceiver processor may be envisioned as functioning as afrequency-domain equalizer (that may be viewed as a frequency-domainfractionally-spaced equalizer) and/or as a frequency-domain rakereceiver that collects a maximum (or near maximum) available/desiredsignal energy to increase/maximize capacity and/or power efficiency ofcommunications. This may be achieved, in some embodiments, by utilizingenergy of a plurality of frequency-domain points whose respective“noise” components are, at least partially, uncorrelated and/orindependent therebetween but whose “desired” signal components comprisea level of correlation/dependence therebetween.

It will be understood that any embodiment or combination/sub-combinationof embodiments described herein and/or in any of the U.S. Provisionalapplications cited herein may be used to provide wireless and/orwireline systems, devices and/or methods. It will also be understoodthat even though embodiments are presented herein in terms of a receiverprocessor reducing/minimizing a mean-squared error quantity, performanceindex and/or cost function (i.e., a recursive and/or non-recursivereceiver processor that yields a Least Mean Squared Error (“LMSE”)), anyother quantity, performance index, algorithm (recursive and/ornon-recursive) and/or cost function other than LMSE (such as, forexample, zero-forcing, least squares, maximum likelihood, maximum aposteriori probability, etc.) may be used in lieu of LMSE or inconjunction with LMSE. Recursive and/or non-recursivealgorithms/receiver processors may also be used whether embodied assoftware, hardware and/or firmware. It will also be understood that theprinciples described herein are applicable to any wireline and/orwireless transmitter/receiver system, device and/or method, includingradar transmitter/receiver systems, devices and/or methods. Furthermore,it will be understood that according with Multiple Input Multiple Output(“MIMO”) embodiments of the invention, the solid signal may, at leastpartially, be transmitted from a first antenna and the dotted signalmay, at least partially, be transmitted from a second antenna.

Further embodiments may be provided as is illustrated by FIG. 4 a. Theseembodiments may be referred to herein as “Case 4.” In these embodiments,a spatial isolation between first and second antennas of a base station(or any other device) is used (relied upon) to attenuate (suppress)matrices ā and ū by an amount “a” (|a|<1). A receiver processor as inembodiments relating to Case 1 may be used to process receivedobservable vectors b and r (expressed as b=B+a āR+n; and r=aūB+ν) toderive information (data) associated with transmitted respective firstand second end-user device signal vectors B and R, as is shown in FIG. 4a. Computer simulation results are presented in FIG. 4 b.Configurations/embodiments of providing return-link communications asillustrated by FIG. 4 a, advantageously allow first and second end-userdevices to send/transmit return-link information (data) to a basestation (and/or any other system element) using respective first (B,blue, or solid) and second (R, red, or dotted) carriers/signals that aretransmitted, by the respective first and second end-user devices,staggered in frequency therebetween but substantially co-channel, usingsubstantially the same resources of an available frequency space,channel and/or bandwidth, as is illustrated in FIG. 1, thus increasing aspectral efficiency measure of the return-link communications. In someembodiments, the staggering in frequency may be equal (or approximatelyequal) to ½T (i.e., one half of the inverse of a signaling interval asis illustrated in FIG. 1). In other embodiments, the staggering infrequency may be equal to one or more other values and/or may varyacross the available frequency space.

Additional embodiments of the present invention may be provided as isillustrated in FIG. 5 a. In these additional embodiments, which may bereferred to herein as relating to “Case 5,” a spatial isolation “a”between first and second antennas of a base station and/or first andsecond antennas of respective first and second end-user devices is usedto provide forward-link communications from the base station to thefirst and second end-user devices, as is illustrated in FIG. 5 a. Areceiver processor (at each end-user device), that may, according tosome embodiments, be configured substantially as in Case 1, may be usedto process received observable vectors b and r (as received by eachend-user device) to derive information (data) associated withtransmitted signal vectors B and R, as is shown in FIG. 5 a. Computersimulation results are presented in FIG. 5 b. Configurations/embodimentsof providing forward-link communications as is illustrated in FIG. 5 a,advantageously can allow first and second end-user devices to receiveinformation (data) from a base station using respective first (B, blue,or solid) and second (R, red, or dotted) carriers that are staggered infrequency therebetween and transmitted by the base station substantiallyco-channel, using substantially the same resources of an availablefrequency space/channel/bandwidth, as is illustrated in FIG. 1, thusincreasing a spectral efficiency measure of the forward-linkcommunications. In some embodiments, the staggering in frequency may beequal (or approximately equal) to ½T (i.e., one half of the inverse of asignaling interval as is illustrated in FIG. 1). In other embodiments,the staggering in frequency may be equal to one or more other valuesand/or may vary across the available frequency space.

Still further embodiments of the present invention may be provided.These still further embodiments may be referred to herein as relating to“Case 6.” In accordance with these still further embodiments, anintentionally-introduced attenuation factor (“a”) may be used tosimulate a spatial isolation that may not be present because eitherfirst and second end-user devices are proximate to one another orbecause the first and second signals (i.e., the blue/solid andred/dotted signals) are transmitted by a base station in the samedirection and are both aimed at a given (same) end-user device.Accordingly, the base station may transmit B and aR (instead of B andR); wherein |a|<1.

For a first embodiment relating to Case 6, a receiver processor at anend-user device may be configured substantially as in Case 1 and mayfirst be used to process the received observable vectors b=B+aāR+n andr=aR+ūB+ν to derive information (data) associated with transmittedsignal vectors B. Once an estimate of B has been derived, it may be usedto perform a cancellation of components related to B (that is,cancellation of the term ūB in r, without noise enhancement of r) thusderiving an estimate of R. Thus, in embodiments of the inventionrelating to Case 6, a two-stage (or a multi-stage) sequential receiverprocessor may be used.

For a second embodiment relating to Case 6, a receiver processor at afirst end-user device, that may, according to some embodiments, beconfigured substantially as in Case 1, may first be used to process thereceived observable vectors b and r to derive information (data)associated with transmitted signal vector B. Once an estimate of B hasbeen derived, the estimate of B may be relayed by the first end-userdevice to a second end-user device via a link (that may be a short-rangelink that is established directly between the first and second end-userdevices) and the estimate of B may be used by the second end-user deviceto perform cancellation of components related to transmitted signalvector B (without noise enhancement) thus deriving an estimate of R.Thus, in embodiments of the invention relating to Case 6, a sequentialreceiver processor may be used wherein the sequential receiver processormay be distributed between the first and the second end-user devices andwherein a processor component that is associated with the secondend-user device receives a first data estimate from the first end-userdevice and uses the received first data estimate from the first end-userdevice to derive a second data estimate that is intended for the secondend-user device; wherein the first data estimate is intended for thefirst end-user device but is sent by the first end-user device to thesecond end-user device to aid the second end-user device to derive thesecond data estimate that is intended for the second end-user device.

Alternatively or in combination with the above, the sequential receiverprocessor may be included in its entirety in the second and/or in thefirst end-user device so that, in some embodiments, the second end-userdevice may not have to rely upon receiving the first data estimate fromthe first end-user device. Instead, the second end-user device mayitself derive the first data estimate (even though the first data and/orany estimate thereof is not intended for the second end-user device) andthen, the second end-user device may use the first data estimate that ithas derived to derive the second data estimate (that is intended for thesecond end-user device). In some embodiments, the second end-user devicemay be configured to derive the first data estimate (via signalprocessing that is not associated with the first end-user device; viasignal processing that is at the second end-user device) and to alsoreceive the first data estimate from the first end-user device (asderived via signal processing that is associated with the first end-userdevice and is at the first end-user device). It will be understood thatthe term first end-user device may, in some embodiments, comprise aplurality of first end-user devices (that may be networked therebetweenand/or may be configured to communicate therebetween directly or viaintervening elements) and/or the term second end-user device may, insome embodiments, comprise a plurality of second end-user devices (thatmay be networked therebetween and/or may be configured to communicatetherebetween directly or via intervening elements).

Accordingly, providing forward-link communications using embodimentsassociated with Case 6, may advantageously allow first and/or secondend-user devices to receive information (data) from a base station usingfirst (B, blue, or solid) and second (R, red, or dotted) carriers thatare staggered in frequency therebetween and transmitted by the same basestation substantially co-channel, using substantially the same resourcesof an available frequency space/channel/bandwidth, as is illustrated inFIG. 1, thus increasing a spectral efficiency measure of theforward-link communications. In some embodiments, the staggering infrequency may be equal (or approximately equal) to ½T (i.e., one half ofthe inverse of a signaling interval as is illustrated in FIG. 1. Inother embodiments, the staggering in frequency may be equal to one ormore other values and/or may vary across an available frequency space.It will be understood that in some embodiments, one or more repeats ofaR, over respective one or more signaling intervals, by a transmitterthat is transmitting aR, may be used to increase an aggregate signalenergy associated with a reception/detection of R (since |a|<1).Accordingly, a probability of error associated with thereception/detection of R may be reduced at a reduction of capacityassociated with the second/red signal, R.

It will be understood that even though principles of frequency-domaincoherent combining of signal samples have been disclosed herein, theprinciples disclosed herein are also applicable to coherent combining oftime-domain signal samples. Accordingly, first and second time-domainpulse trains may be transmitted, for example, that may be staggeredtherebetween by, for example, one half of a signaling interval (or anyother interval), creating a time-domain interleaved/staggered blue-redpulse train analogous to the interleaved/staggered blue-redfrequency-domain pulse train of FIG. 1. It will also be understood thatone or more pilot signals, that may be transmitted by a transmitter thatis also transmitting the first and/or the second signals, may be used bya receiver to determine/estimate one or more parameters that are neededfor signal processing at the receiver. Further, it will also beunderstood that receiver signal processing embodiments, as describedherein, may also be used to reduce a level of intermodulationinterference by reducing a power requirement of a transmitter, as willsurely be appreciated by those skilled in the art. Also, those skilledin the art will recognize that one or more subcarriers of the dottedsignal (i.e., of the dotted OFDM carrier; see FIG. 1) may be configuredto carry/transport Forward Error Correction (“FEC”) information tofurther aid in improving communications performance at a receiver.

According to further embodiments of the present invention, first andsecond receiver chains, comprising respective first and second Low NoiseAmplifiers (“LNAs”), may be used by a receiver to derive thefrequency-domain observable vectors b and r, respectively. These furtherembodiments of the present invention may, for example, relate to amulti-antenna receiver/transmitter, method and/or device and/or to aMIMO receiver/transmitter, method and/or device, as will be appreciatedby those skilled in the art. Accordingly, the noise vectors n and ν maybe statistically independent therebetween. It will be understood that areceiver, comprising the first and second receiver chains and/or anyother configuration/embodiment associated with the present invention,may be a receiver of a mobile or transportable device (e.g., a receiverof a wireless terminal or computer) or a receiver of a fixed device(e.g., a receiver of a base station, DSL/cable modem or any other accesspoint in a home or business). It will also be understood that in someembodiments, respective first and second antennas that may be associatedwith the first and second receiver chains may be spaced apart (i.e., maybe at a distance) therebetween and/or may be configured topreferentially receive electro-magnetic energy over respective first andsecond polarizations that may be different therebetween. In otherembodiments, the first and second antennas may be substantiallyco-located. In further embodiments, the first and second antennas maycomprise a single antenna subsystem that may be used to providerespective first and second signals to the first and second receiverchains/LNAs.

Those skilled in the art will appreciate that, in some embodiments, areceiver comprising a single receiver chain (and a single antennasubsystem) may be used instead of a receiver comprising two receiverchains (and two respective antennas) as described above. In someembodiments, a correlation that may exist between the noise vectors nand ν may not substantially degrade a communications performance, suchas, for example, a bit error-rate, or the communications performance maybe degraded by a small/acceptable amount. In some embodiments, acorrelation that may exist between the noise vectors n and ν may notsubstantially degrade communications performance if the quantity δ^(T)(of the decision variable γ^(T)b+δ^(T)r) is complex-valued and/orrepresents a rotation. In rotating r, the noise ν is also rotated,de-correlating n and ν.

Further to the embodiments described above and/or in the U.S.Provisional applications cited herein, including all combinations and/orsub-combinations thereof, a transmitter may be configured to transmit asignal vector B for the solid signal and the transmitter may also beconfigured to transmit a signal vector R=ā⁻¹ B for the dotted signal(wherein “ā⁻¹” denotes inverse of ā). Accordingly, a receiver may beconfigured to derive frequency-domain observable vectors b=2B+n andr=(ā⁻¹+ū)B+ν. Further, a receiver processor may be configured to combinethe two frequency-domain observable vectors b and r, yieldingb′_(k)=γ^(T)b+δ^(T)r, such as for example, a mean-squared performancemeasure between b′_(k) and B_(k) (a k^(th) element of B) is minimized orreduced. It will be understood that the superscript “T” on a vectordenotes transpose or conjugate transpose (i.e., Hermitian transpose), asappropriate. Furthermore, it will be understood that B_(k) may becomplex-valued and denotes the k^(th) element of the data vector B (k=1,2, . . . , N). Also, it will be understood that the receiver vectors γand δ may, in some embodiments, take-on different values for differentvalues of the index k.

In some embodiments, a receiver may be configured to generate at least2N samples of a received signal, x(t)+N(t), over at least a signalinginterval, T, thereof. That is, letting the received signal bey(t)=x(t)+N(t), wherein x(t) denotes a desired signal component and N(t)denotes noise and/or interference, the receiver may be configured togenerate a set of 2N samples, {y(t₁), y(t₂), y(t₃), y(t₄), y(t₅), . . ., y(t_(2N))}, and to use a first subset of the 2N samples, comprising,for example, N of the 2N samples, that may comprise, for example, oddindexed samples {y(t₁), y(t₃), y(t₅), . . . } of the 2N samples, to forma first Discrete Fourier Transform (“DFT”) and/or a first Fast FourierTransform (“FFT”), that may be a first N-point DFT and/or a firstN-point FFT at the frequencies k/T; k=1, 2, . . . , N; and to use asecond subset of the 2N samples, comprising, for example, M of the 2Nsamples, that may comprise, for example, even indexed samples {y(t₂),y(t₄), y(t₆), . . . } of the 2N samples, to form a second DFT and/or asecond FFT, that may be a second M-point DFT and/or a second M-point FFTat the frequencies (2n+1)/2T; n=1, 2, . . . , M. In some embodiments,M=N; in other embodiments, M<N; in further embodiments, M>N. The firstsubset of the 2N samples may also be referred to herein as the first setof samples or the first set of N discrete-time samples and the secondsubset of the 2N samples may also be referred to herein as the secondset of samples or the second set of N discrete-time samples.

It will be understood that the first subset of the 2N samples may, inaccordance with some embodiments of the invention, comprise a number ofsamples that is not equal to a number of samples associated with thesecond subset of the 2N samples. Similarly, the same may be stated withrespect to the terminology “first set of samples” and “second set ofsamples,” and with respect to the terminology “first set of Ndiscrete-time samples” and “second set of N discrete-time samples.” Tofurther clarify, the “N” in “first set of N discrete-time samples” andthe “N” in “second set of N discrete-time samples” does not necessarilyconstrain these terms to be associated with an equal number “N” ofsamples. A number of samples associated with the “first set of Ndiscrete-time samples” may be different than a number of samples that isassociated with the “second set of N discrete-time samples.”

In reference to FIG. 1, it will be understood that, according toembodiments of the present invention, a transmitted/received signal maycomprise N₀ first sub-carriers (the solid sub-carriers of FIG. 1) thatmay be orthogonal therebetween and M₀ second sub-carriers (the dottedsub-carriers of FIG. 1) that may be orthogonal therebetween but may notbe orthogonal to the N₀ first sub-carriers (e.g., in some embodiments ofthe invention, at least one of the M₀ second sub-carriers is notorthogonal to any one of the N₀ first sub-carriers; or at least one ofthe M₀ second sub-carriers is not orthogonal to at least one of the N₀first sub-carriers); wherein N₀≧2 and M₀≧N₀ or M₀<N₀, and wherein M₀≧0.Further, it will be understood that a receiver may be configured togenerate 2N′ samples of the transmitted/received signal; wherein N′≧N₀;and to perform a first transformation on a first sub-set of the 2N′samples, comprising N″ samples; wherein N″≦2N′; and to perform a secondtransformation on a second sub-set of the 2N′ samples, comprising N′″samples; wherein N′″≦2N′; and to combine an element of the firsttransformation with an element of the second transformation (as isfurther illustrated by the flow-chart of FIG. 11 and by FIGS. 8, 9 and10). In some embodiments, N″=N′″=N′.

In some embodiments, the signal y(t)=x(t)+N(t) may be a passband signal,centered at a carrier frequency f_(c) and comprising a bandwidth N/T(i.e., the signal y(t) may occupy and/or be allocated frequencies fromf_(c)−N/2T to f_(c)+N/2T), and a receiver may be configured to generateany desired number of samples of y(t) over a T-seconds signalinginterval thereof. In other embodiments, the passband signal y(t) may beshifted and/or translated in frequency so as to be centeredsubstantially at the frequency N/2T after it has been frequencyshifted/translated (thus comprising frequency content from substantiallyzero Hz to NIT Hz after it has been frequency shifted/translated), andthe receiver may be configured to generate samples of y(t) by operatingon the frequency shifted/translated version of y(t). In furtherembodiments, the passband signal y(t) may be shifted/translated infrequency so as to be centered substantially at zero frequency after ithas been frequency shifted/translated (and thus comprise frequencycontent from substantially −N/2T Hz to N/2T Hz), and the receiver may beconfigured to generate samples by operating on this frequencyshifted/translated version of y(t).

In yet further embodiments, the passband signal y(t) may beshifted/translated in frequency so as to be centered substantially at afrequency f_(c)′; wherein f_(c)′ may be smaller than f_(c) or greaterthan f_(c); and the shifted/translated signal may thus comprisefrequency content from substantially f_(c)′−N/2T Hz to f_(c)′+N/2T Hz,and the receiver may be configured to generate samples by operating onthis frequency shifted/translated version of y(t). In some embodiments,the desired number of samples over the T-seconds signaling interval is2N. In other embodiments, the desired number of samples over theT-seconds signaling interval is N. In further embodiments, the desirednumber of samples over the T-seconds signaling interval may be anydesired number of samples that may differ from N or 2N.

Accordingly, a receiver may be configured, in some embodiments, togenerate at least 2N time-domain samples of the received signalx(t)+N(t) over at least the T-seconds signaling interval using areceiver sampling rate of at least 2N/T. In further embodiments, thereceiver may be configured to generate at least N time-domain samples ofthe received signal x(t)+N(t) over at least the T-seconds signalinginterval using a receiver sampling rate of at least N/T. It will beunderstood that, in some embodiments, a receiver sampling rate mayexceed N/T and/or 2N/T, while in other embodiments, a receiver samplingrate may be smaller than NIT and/or 2N/T. In some embodiments, areceiver sampling rate may depend upon an autocorrelation function thatis associated with N(t). Given that a spectrum of y(t), on a positivefrequency axis, is centered at a frequency f_(c)′, and thus the spectrumof y(t) comprises frequency content from substantially f_(c)′−N/2T Hz tosubstantially f_(c)′+N/2T Hz, an autocorrelation function of N(t),subject to ideal passband filtering of y(t) about f_(c)′, may be shownto be:

R(τ)=2η₀(N/T){[Sin π(N/T)τ]/[π(N/T)τ]} Cos 2πf _(c)′τ;

wherein η₀ may be a constant and may represent a noise density, such asa noise power spectral density or a noise energy spectral density.

Accordingly, setting 2πf_(c)′τ=π/2 yields R(τ)=0 for τ=1/(4f_(c)′). Wethus observe, that if, for example, we set f_(c)′=N/2T, we will haveR(τ)=0 for τ=T/2N and, a receiver that is configured to sample at a rateof 2N/T will yield 2N samples over T; wherein each sample of the 2Nsamples comprises a noise component that is uncorrelated from any othernoise component associated with any other of the 2N samples. Thoseskilled in the art know that uncorrelated noise components implyindependent noise components, assuming Gaussian noise statistics.Accordingly, if all 2N noise components are independent therebetween,and a first set of the 2N samples is used to form b, while a second setof the 2N samples is used to form r; wherein the second set of the 2Nsamples does not intersect (i.e., does not have any elements in commonwith) the first set of the 2N samples, the n and the ν noise vectorswill be uncorrelated and independent therebetween.

It may be observed from the R(τ) equation above that if f_(c)′ is, forexample, doubled, a sampling rate of the receiver may also be doubled,while the receiver may continue to provide samples of y(t) comprisingnoise components that are uncorrelated and/or independent therebetween.Accordingly, in some embodiments, a receiver may be configured toshift/translate, in frequency, a received signal y(t) such as to centera spectrum of y(t) at a value of f₀′ that allows the receiver to takemore than 2N samples of y(t), over T, while maintaining noise componentsbetween samples uncorrelated and/or independent. As such, the more than2N samples may now be used to define more than two subsets. The morethan two subsets of the more than 2N samples may be used to provide morethan two DFTs and/or FFTs, which may be combined, according to theprinciples disclosed herein, to allow further improvements incommunications performance and/or capacity.

Specifically, R(τ)=0 for τ=1/(4 f_(c)′), as was stated earlier.Accordingly, if, for example, we set f_(c)′=N/T, we will have R(τ)=0 forτ=T/4N and, a receiver that is configured to sample at a rate of 4N/Twill yield 4N samples over T; wherein each sample of the 4N samplescomprises a noise component that is uncorrelated from any other noisecomponent associated with any other of the 4N samples. Thus, if all 4Nnoise components are independent therebetween, a first subset of the 4Nsamples comprising, for example, N samples, may be used via a firstN-point FFT to form a “b′” at, for example, the frequencies (k+N)/T;k=1, 2, . . . , N; while a second subset of the 4N samples comprising,for example, N samples, may be used to form a “r′,” at, for example, thefrequencies (k+N+½)/T; k=1, 2, . . . , N; wherein, as before, the secondsubset of the 4N samples does not intersect the first subset of the 4Nsamples, thus allowing the n′ noise vector (i.e., the noise component ofb′) and the ν′ noise vector (i.e., the noise component of r′) to beuncorrelated and independent therebetween. But there are still 2Nsamples that have not been used. These remaining 2N samples may be usedto form a further b″ at, for example, the frequencies (k+N+¼)/T; k=1, 2,. . . , N; and a further r″ at, for example, the frequencies (k+N+¾)/T;k=1, 2, . . . , N; and wherein at least some of b′, r′, b″ and r″ (andin some embodiments all of b′, r′, b″ and r″) may be combinedtherebetween, for example, using a LMSE criterion, or any othercriterion, as has previously been discussed herein. This technique mayclearly be applied to any case wherein a number of samples of y(t), overT, is an integer multiple of N. In other embodiments, the number ofsamples of y(t), over T, may not be an integer multiple of N.

In some embodiments, a second set of samples (or a second set ofdiscrete-time samples), that may comprise N samples, may be based upon afirst set of samples (or a first set of discrete-time samples), that maycomprise N samples. In further embodiments, the second set of samplesmay be derived from the first set of samples by multiplying the firstset of samples by a sinusoidal function or by an exponential functionthat may be a complex exponential function (e.g., a complex sinusoidalfunction). In additional embodiments, the first set of samples may beused to generate a first Discrete Fourier Transform (“DFT”) and/or afirst Fast Fourier Transform (“FFT”), at frequencies of k/T; k=1, 2, . .. , N; and the second set of samples may be used to generate a secondDFT and/or a second FFT at frequencies of (2n+1)/2T; n=1, 2, . . . , M;wherein M may be equal to N, M may be greater than N or M may be lessthan N.

It will be understood that any embodiment or combination/sub-combinationof embodiments described herein and/or in any of the U.S. Provisionalapplications cited herein may be used to provide wireless and/orwireline systems, devices and/or methods. It will also be understoodthat even though embodiments of the present invention are presentedherein in terms of a receiver processor that is configured toreduce/minimize a mean-squared error quantity, performance index and/orcost function (i.e., a receiver processor that yields one or more LeastMean Squared Error (“LMSE”) receiver observables), any other quantity,performance index and/or cost function other than LMSE and/or anyvariation of LMSE (such as, for example, Kalman, fast Kalman,LMS/Newton, sequential regression, random-search, latticestructure/predictor, zero-forcing, least squares, recursive leastsquares, maximum likelihood sequence estimation, maximum a posterioriprobability, maximum ratio combining and/or any variations, combinationsand/or sub-combinations thereof, etc.) may be used, as will beappreciated by those skilled in the art, in lieu of LMSE or inconjunction and/or in combination with LMSE.

It will be understood that in some embodiments such as, for example, inOFDM/OFDMA embodiments, wherein a plurality of spatially diversechannels and/or communications links may be associated with a singlecarrier, wherein the plurality of spatially diverse cannels and/orcommunications links may correspond to a respective plurality of users,a respective plurality of receiver vectors (in γ and/or δ) in may beused to accommodate the plurality of channels/users. Each channel of theplurality of channels may be associated with a different signal-to-noiseratio, necessitating, according to some embodiments, its own(individually optimized) γ and/or δ vectors. The γ and/or δ vectors maybe updated (iteratively and/or non-iteratively) responsive to, forexample, one or more measurements of, for example, a channel'ssignal-to-noise ratio.

In a conventional OFDM system, an OFDM carrier, comprising a pluralityof sub-carriers, may be amplified, prior to transmission, via a singlePower Amplifier (“PA”). As such, owing to an output power requirement ofthe conventional OFDM system, the PA may be driven to operate (at leastto some extent) in a non-linear region thereof, generating non-lineardistortion which may adversely impact the conventional OFDM system,particularly when the OFDM carrier includes at least some sub-carriersthat are based upon a high-order modulation alphabet, such as, forexample, 64-QAM, 128-QAM, 256-QAM, 1024-QAM, etc.

In some embodiments of the present invention, at least two PAs areprovided wherein at least a first one of the at least two PAs is used toamplify at least a portion of the “solid” waveform/signal (see FIG. 1),at least a second one of the at least two PAs is used to amplify atleast a portion of the “dotted” waveform/signal (see FIG. 1) and whereinrespective outputs of the at least two PAs are combined, using a signalcombiner, prior to the two amplified signals being transmitted over oneor more propagation media/channels via one or more antennas. FIG. 6 isillustrative of a wireless OFDM/OFDMA system and/or method, according tovarious embodiments of the present invention. It will be understood,however, that the principles disclosed herein are also applicable tonon-wireless OFDM/OFDMA systems and/or methods. It will also beunderstood that the respective outputs of the at least two PAs of FIG. 6need not be combined, according to some embodiments of the presentinvention, but instead, may be used to excite respective at least firstand second antenna elements (not illustrated in FIG. 6) or respective atleast first and second non-wireless transmission media. Further to theabove, it will be understood that the label “Solid Waveform” as itappears in FIG. 6 means “at least a portion of the Solid Waveform,” or“at least some subcarriers of the Solid Waveform.” Similarly, it will beunderstood that the label “Dotted Waveform” as it appears in FIG. 6means “at least a portion of the Dotted Waveform,” or “at least somesubcarriers of the Dotted Waveform.” Accordingly, each one of the PAs,as illustrated in FIG. 6, may operate at a lower output power level,providing greater linearity, reducing a non-linear distortion thereofand allowing for improved performance of an OFDM/OFDMA carrier, that mayinclude at least some sub-carriers that are based upon a high-ordermodulation alphabet, such as, for example, 64-QAM, 128-QAM, 256-QAM,1024-QAM, etc.

According to further embodiments of the present invention, an OFDM/OFDMAcarrier comprising N sub-carriers (N≧2), which may conventionally bebased upon a single N-point FFT and/or a single N-point IFFT (or asingle N-point DFT/IDFT) may instead be based upon Q, Q≧2, J-point FFTsand/or Q J-point IFFTs (or Q J-point DFTs/IDFTs), wherein J≦N in someembodiments. In other embodiments, however, J>N. (It will be understoodthat, according to some embodiments, at least one FFT and/or IFFT of theQ “J-point FFTs and/or IFFTs” may be based upon and/or include a numberof points that is different than J.) Each one of the Q “J-point FFTsand/or IFFTs,” which may be representing a grouping of less than Nsub-carriers (and in some embodiments a grouping of up to N sub-carriersor more), may be provided to one of Q respective PAs, as is illustratedin FIG. 7. (It will be understood that FIG. 7 is only illustrative andassumes a wireless environment and that the principles disclosed hereinalso apply to any other non-wireless environment and/or transmissionmedium.) Following amplification, Q respective outputs of the Qrespective PAs may be combined by a signal combiner and used to excitean antenna or antennas (or any other element of a wireless/non-wirelesstransmission medium), as is, for example, illustrated in FIG. 7. It willbe understood that in some embodiments, at least a first and a secondoutput of respective first and second PAs, of the Q PAs, may be used toexcite respective first and second antennas (not illustrated in FIG. 7).Some embodiments of systems, methods and/or devices according to FIG. 6and/or FIG. 7 are devoid of the signal combiner that is illustrated inFIG. 6 and in FIG. 7. In such embodiments, there is a one-to-onecorrespondence between a number of PA outputs and a number of antennaelements, wherein each PA output is associated with, and is used toexcite/feed/drive, a respective antenna element.

It will also be understood that any OFDM/OFDMA system/method/device,conventional or otherwise, including wireless and non-wireless (i.e.,wireline, cable, fiber optical, etc.) systems, methods and/or devices,or any other multi-carrier system, method and/or device (that may not bebased upon OFDM/OFDMA principles), may be based on a transmitterarchitecture/method as is described herein and is illustrated in FIG. 6and/or FIG. 7, to reduce (or minimize) an output power level requirementof one or more individual PAs, improve linearity associated withamplification and/or reduce (or eliminate) a communications performancepenalty due to non-linear distortion, while increasing a systemthroughput (or capacity) by allowing higher-orderconstellation/modulation alphabets to be used, such as, for example a256-QAM or even a 1024 QAM constellation/modulation alphabet. In willalso be understood that embodiments as described herein and illustratedin FIGS. 8, 9, 10 and/or 11, may be combined in part or in whole withembodiments as described herein and illustrated in FIGS. 6 and/or 7.

Additional embodiments relating to pre-distortion of data by atransmitter will now be presented. In Provisional Application No.61/163,119, filed on 25 Mar. 2009 and incorporated herein by referencein its entirety as if set forth fully herein, at the top of page 3thereof, it is stated that “the vector R may be set equal to εB . . . ”and that “ . . . ε may be a scalar (complex-valued, real or imaginary)or a matrix (complex-valued, real or imaginary).” Accordingly, a seconddata vector, such as, for example, the data vector R, may be generatedvia a transformation, that may be a linear and/or a non-lineartransformation, of a first data vector, such as, for example, the datavector B, such that an element/component of the second data vector(e.g., an element/component of R) may depend upon a plurality ofelements/components of the first data vector (e.g., may depend upon aplurality of elements/components of B), wherein the element/component ofthe second data vector may comprise a linear and/or non-linearcombination of elements/components of the first data vector. In someembodiments of the invention, the second data vector (e.g., the datavector R) may comprise a frequency-shifted version of at least someelements/components/dimensions of the first data vector (e.g., the datavector B) and, the second data vector, may, according to someembodiments, also include a phase rotation relative to the first datavector; wherein the phase rotation may be 90° (or π/2 radians), in someembodiments. The phase rotation may be used advantageously to furtherde-correlate noise/interference components of the second data vector (R)relative to noise/interference components of the first data vector (B)at a receiver that is configured to process the two data vectors (B andR), for example, as described earlier.

Further to the above, in Provisional Application No. 61/119,593, thatwas filed on 3 Dec. 2008 and is incorporated herein by reference in itsentirety as if set forth fully herein, towards the middle of page 3thereof, it is stated that “In additional embodiments, a signal (solidand/or dotted), or at least a portion thereof, may be subjected to apartial pre-distortion by a transmitter, whereby a residual level ofinterference remains therein upon reception by a receiver, and may alsobe subjected to equalization by the receiver in order to reduce theresidual level of interference.” Accordingly, a partial pre-distortionlevel may be provided by a transmitter to a signal (e.g., to a datavector) such that a level of interference remains upon reception of thesignal by a receiver and the receiver may then be relied upon to furtherprocess the signal in order to reduce the level of interference thatremains.

Based on the above, additional embodiments of systems/devices/methodsmay be provided wherein a content/element/component of a signal, whereinsaid signal may comprise, for example, an OFDM/OFDMA carrier comprisingN data elements and/or N sub-carriers (that may be orthogonaltherebetween), may be subjected to a pre-distortion, that may be apartial pre-distortion, such that the content/element/component of thesignal may be spread, for example, in frequency and/or in time, over anavailable/predetermined frequency space (and/or time space) in order toprovide frequency/time diversity protection. In some embodiments, saidsignal may comprise, for example, an OFDM/OFDMA carrier comprising Ndata elements and/or N sub-carriers that may be orthogonal therebetween,non-orthogonal therebetween or partially orthogonal therebetween (e.g.,a second element/subcarrier is orthogonal to a first element/subcarrierwhile a third element/subcarrier is not orthogonal to the firstelement/subcarrier).

Accordingly, the data vector C′ may be generated from the data vector Cin many different ways, by subjecting C to linear and/or non-linearprocessing. In some embodiments, C′ may be generated from C bysubjecting C to a linear transformation (e.g., by multiplying C by amatrix, that may, according to some embodiments of the presentinvention, be a square N×N matrix). In some embodiments, C′ may compriseN elements/components/dimensions, wherein at least oneelement/component/dimension of C′ comprises a linear superposition ofelements/components/dimensions of C and wherein, in some embodiments,each element/component/dimension of C′ comprises a linear superpositionof elements/components/dimensions of C. In some embodiments, the linearsuperposition of elements/components/dimensions of C comprises arotation (and is devoid of amplitude modification) wherein theelements/components/dimensions of C are each rotated (by an angle thatis negative, positive or zero) and are then summed therebetween to formthe linear superposition. According to further embodiments of thepresent invention, the linear superposition ofelements/components/dimensions of C is based upon/includes all Nelements/components/dimensions of C, as would be the case, for example,if the N elements/components/dimensions of C were subjected to a Fouriertransform, such as, for example, a Fast Fourier Transform (FFT) and/or aDiscrete Fourier Transform (DFT).

The data vector C′ may be augmented by one or more pilot symbols andthen transmitted over a plurality of frequency/time channels that may beorthogonal therebetween. Prior to the augmentation of C′ by the one ormore pilot symbols, C′ is limited to N elements/components/dimensionsand/or data sub-carriers. In some embodiments, following theaugmentation of C′ by the one or more pilot symbols, the augmented C′,denoted as AC′, may comprise N+P, P≧1, elements/components; wherein P ofsaid pilot symbols are associated with respective P pilot sub-carriersthat are provided over-and-above the N data sub-carriers. In otherembodiments, following the augmentation of C′ by the one or more pilotsymbols, C′remains limited to N elements/dimensions; wherein said pilotsymbols are provided as imbedded within the N elements/dimensions and/ordata sub-carriers of C′.

Accordingly, in some embodiments, AC′ may be transmitted over N+Pfrequency/time channels wherein, in some embodiments, a first portion ofthe N+P frequency/time channels may occupy a first frequency/timeinterval and wherein a second portion thereof may occupy a secondfrequency/time interval that may not be contiguous with the firstfrequency/time interval. The N+P frequency/time channels may correspondto respective N+P sub-carriers that may be orthogonal therebetween. Itwill be understood that the terminology that is used above, in referringto the first and second non-contiguous frequency/time intervals, refersto embodiments wherein AC′ is transmitted using, for example,frequencies from f_(x) to f_(x)+Δ_(x) and frequencies from f_(y) tof_(y)+Δ_(y), wherein Δ_(x)+Δ_(y) denotes an aggregate RF bandwidth thatis required for the transmission of AC′, using an OFDM/OFDMA technology,over a signaling interval T.

In some embodiments, f_(y) is separated from f_(x)+Δ_(x) by asubstantial frequency interval over which an authority for thetransmission of AC′ has not been provided; wherein said authority may bea regulatory/government/industrial authority or any other authority thatmay relate to a commercial, business, financial, political and/orinterference concern. For example, according to a broadband embodiment,the aggregate RF bandwidth may have a value of 100 MHz (Δ_(x)+Δ_(y)=100MHz), that may not be available contiguously (i.e., may not be availableas one continuous block of spectrum) to an entity desiring to transmitAC′. Accordingly, the entity may select to transmit AC′ using, forexample, the following parameters: f_(x)=1 GHz, Δ_(x)=40 MHz, f_(y)=1.4GHz and Δ_(y)=60 MHz. It will be understood that any other set of valuesfor the parameters listed above may be used to define a broadband (ornon-broadband) embodiment. It will also be understood that the broadband(or non-broadband) embodiment may be based upon a Time Division Duplex(TDD) protocol and/or a Frequency Division Duplex (FDD) protocol.

In an analogous way to using non-contiguous frequency intervals, asdescribed above, two or more non-contiguous time intervals may be used,according to further embodiments, in conjunction with (or without theuse of) two or more non-contiguous frequency intervals to transmit anaugmented (by the one or more pilot symbols) vector C′ and/or a sequenceof augmented vectors C′.

It will be appreciated by those of skill in the art that by havingconstructed C′ based upon C, as is illustrated above, at least one dataelement/component of C′, and in some embodiments each one of the N dataelements/components of C′ comprises a value (complex, imaginary or real)that is related to (i.e., is a function of and/or depends upon) aplurality of data elements/components of C and that according to furtherembodiments, at least one data element/component of C′, and in someembodiments each one of the N data elements/components of C′ comprises avalue (complex, imaginary or real) that is related to (i.e., is afunction of and/or depends upon) all N data elements/components of C.Stated differently, at least one element/component of C is distributed(e.g., a power and/or energy content thereof is distributed) over atleast first and second elements/components/dimensions of C′.Accordingly, if during transmission of C′ the second element/componentof C′, for example, is degraded due to a channel anomaly such as, forexample, a fade and/or interference, a receiver that is configured toreceive and process C′ in order to derive an estimate of C may still beable to derive a reliable estimate of C based upon a frequency/timediversity that is provided by C.

It will be understood that in some embodiments, prior to transmission ofAC′, AC′ may be further pre-distorted/transformed by using a channelmatrix, whose elements comprise (and/or are based upon) an inverse of achannel response and/or a complex conjugate of a channel response.Having further pre-distorted/transformed AC′ by, for example, havingmultiplied AC′ by the channel matrix, as the further pre-distortedvector AC′ propagates through the channel, a channel-induceddegradation, such as, for example, a channel fading may be reduced. Thechannel matrix may be used, as described above, to furtherpre-distort/transform the vector AC′ in any Time Division Duplex (TDD)embodiment and particularly in broadband TDD embodiments wherein asignaling interval T is small compared to a variation that may beexperienced by the channel matrix. Other embodiments that are not basedupon TDD may also use a channel matrix to further pre-distort/transformthe vector AC′. FIG. 12 illustrates embodiments of systems/methods thatare based upon the above description.

As is illustrated in FIG. 12 (top trace), a data vector C, that may,according to some embodiments, be a data vector that is defined in afrequency domain, comprising N data elements (C₀, C₁, . . . , C_(N−1))is to be transmitted by a transmitter. Each one of the N data elementsmay be real-valued, imaginary-valued or complex-valued and each one ofthe N data elements may take-on values from any desired signalconstellation such as, for example, BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM,etc. Prior to transmission of C by the transmitter, C is subjected to atransformation (pre-distortion) which, as is illustrated by the secondtrace of FIG. 12, may be based upon a Fourier Transform, which may bebased upon a N-point Discrete Fourier Transform (DFT) and/or a FastFourier Transform (FFT) with any desired/appropriate scaling factor,such as, for example, (1/N)^(1/2), instead of the conventional scalingfactor of 1/N. The Fourier transform operation is labeled as “FFT(T)” inFIG. 12; “FFT” for Fast Fourier Transform and “(T)” for Transmitter. Itwill be understood, however, that what is shown in FIG. 12 isillustrative, may relate to some embodiments, and that, in otherembodiments, C may be subjected to any othertransformation/pre-distortion (linear or otherwise) as desired and/orappropriate. A transformed C will be denoted as C′. In some embodiments,in addition to the above (or instead of the above), a number of nullsubcarriers may be added to C′ (or to C) so that a dimensionality of C′(or C) increases beyond N; wherein each one of the null subcarrierscomprises zero amplitude/magnitude and may be placed/positionedanywhere, as desired, on a frequency axis. In further embodiments, inaddition to the above (or instead of the above), one or more subcarriersof C′ (or C) that include a non-zero amplitude/magnitude may be deletedand replaced with respective null subcarriers each comprising a zeroamplitude/magnitude. This technique of deleting and replacing one ormore non-zero amplitude/magnitude subcarriers of C′ (or C) withrespective null subcarriers may be used, in some embodiments, to providea frequency-domain pulse position modulation system/method/device aswill be appreciated by those skilled in the art. It is understood thatthe one or more subcarriers of C′ (or C) that are deleted and replacedby null subcarriers may be kept and transmitted over one or moresuccessive signaling intervals.

Following the transformation (pre-distortion) of C, as is describedabove and/or is illustrated by the second trace of FIG. 12, a number P(P≧1) of pilot symbols (e.g., pilot sub-carriers) may be added to thetransformed C, denoted as C′, thus forming an Augmented C′, denoted asAC′ in FIG. 12. It will be understood that in some embodiments, informing AC′ from C′, one or more elements of C′ may be rearranged (e.g.,the first element of C′ (C′₀) may become the last element of AC′(AC′_(N+P−1))). It will also be understood that pilot symbols may beinserted in locations other than those illustrated by the third trace ofFIG. 12. Those skilled in the art will appreciate that C may initiallyincluding only M data elements (M≦N); C may then be mapped onto N≧Msubcarriers (with at least one subcarrier having zero magnitude if M<N)thus generating a frequency-domain version/representation of C; anN-point FFT may then be performed on C, following the mapping of C ontothe N subcarriers, in order to generate C′; the pilot symbols may thenbe added to C′ in order to create AC′, as described earlier, and then aN+P point IFFT may be performed on AC′ prior to transmission thereofover a channel. Further to the above, prior to transmission of AC′ overthe channel, AC′ may be operated upon by another matrix (see bottomtrace of FIG. 12), that, according to some embodiments, depends upon achannel matrix/characteristic and may be an estimate of an inverse ofthe channel matrix/characteristic and/or an estimate of a complexconjugate of the channel matrix/characteristic. The bottom trace of FIG.12 illustrates that, prior to transmitting AC′, AC′ may bepre-multiplied by a matrix that, in some embodiments, may be an estimateof an inverse of the channel matrix. Further, the bottom trace of FIG.12 illustrates that, provided that the estimate of the inverse of thechannel matrix is accurate, a channel-induced distortion (or achannel-induced amplitude and/or phase perturbation) may besubstantially negated by the pre-multiplied AC′, allowing AC′ to bereceived by a receiver, substantially devoid of channel-induceddistortion/perturbation, as is illustrated by the bottom trace of FIG.12. It will be understood that the matrix which is used to pre-multiplyAC′, as is discussed above and is illustrated by the bottom trace ofFIG. 12, may be any matrix, including but not limited to an estimate ofan inverse of the channel matrix (or a variant thereof) and an estimateof a complex conjugate of the channel matrix or a variant thereof.

In further embodiments, AC′ may be transmitted by a transmitter devoidof any pre-distortion and/or pre-multiplication by a matrix that isrelated to a channel matrix or to an estimate of the channel matrix. Insuch embodiments, a receiver may be relied upon to compensate for achannel-induced distortion, as is illustrated in FIG. 13. The receiverof FIG. 13 is configured to force the channel-induced distortion to zeroby estimating and using an inverse of a channel matrix. However, asthose skilled in the art know, other receiver processors, such as, forexample, Least Mean Squared Error (LMSE) may be used instead of (or incombination with) the receiver of FIG. 13.

In some embodiments, the matrix that is used to pre-multiply AC′comprises at least one element that is determined pseudo-randomly inaccordance with a statistical distribution, such as, for example, astatistical distribution that is Normal/Gaussian, Bernoulli, Geometric,Pascal/Negative Binomial, Exponential, Erlang, Weibull, Chi-Squared, F,Student's t, Rice, Pareto, Poisson, Binomial, Uniform, Gamma, Beta,Laplace, Cauchy, Rayleigh, Maxwell and/or any other statisticaldistribution. In some embodiments each one of the elements of the matrixthat is used to pre-multiply AC′ is determined pseudo-randomly inaccordance with a statistical distribution. It will be understood that,in some embodiments, different elements of the matrix that is used topre-multiply AC′ may be determined pseudo-randomly by respectivedifferent statistical distributions; however, this may not be necessaryin some embodiments. Accordingly, in some embodiments, all elements ofsaid matrix that is used to pre-multiply AC′ are determined based uponone statistical distribution. It will also be understood that astatistical distribution may be a truncated statistical distributionwherein a random variable that is associated with the statisticaldistribution is precluded from taking-on values over one or more ranges.

In further embodiments, the matrix that is used to pre-multiply AC′comprises a first matrix and a second matrix and, in some embodiments,the matrix that is used to pre-multiply AC′ comprises a product of thefirst matrix and the second matrix wherein the first matrix ismultiplied from the right (i.e., post-multiplied) by the second matrix.In some embodiments, the first matrix is related to the channel matrix(or an estimate of the channel matrix) and the second matrix is notrelated to the channel matrix (is independent of the channel matrix) andincludes at least one element that is determined pseudo-randomly basedupon a statistical distribution, as discussed above. Said second matrixthat includes at least one element that is determined pseudo-randomly,may be used to scramble and/or further pre-distort/alter AC′ prior totransmission thereof to thereby provide increased communicationssecurity, covertness and/or privacy. In some embodiments of theinvention, the second matrix may be used to scramble/alter at least one(and in some embodiments all) of the data elements of AC′ while leavingat least one (and in some embodiments all) of the pilot symbols of AC′unscrambled/unaltered. In further embodiments, all pilot symbols of AC′are also scrambled.

It will be understood that any element, row and/or column of said secondmatrix, may be generated pseudo-randomly (as mentioned above) using, forexample, one or more of the teachings of application Ser. No.12/620,057, entitled Waveforms Comprising a Plurality of Elements andTransmission Thereof, filed on 17 Nov. 2009 and assigned to the assigneeof the present invention, the disclosure of which is hereby incorporatedherein by reference in its entirety as if set forth fully herein.Further, the disclosures of all applications that are cited in the“CLAIM FOR PRIORITY” section of application Ser. No. 12/620,057 areassigned to the assignee of the present invention and the disclosures ofall of which are hereby incorporated herein by reference in theirentirety as if set forth fully herein.

Specifically, the following is a reproduction of Page 35, lines 15-23 ofPCT Application No. PCT/US2006/020417, filed May 25, 2006, whichcorresponds to PCT Publication No. WO 2007/001707, published Jan. 4,2007: In embodiments of the invention where a bandwidth of a signal tobe transmitted by a transmitter (such as the transmitter illustrated inFIG. 7) exceeds a bandwidth limit associated with an antenna and/orother element of the transmitter, the signal may bedecomposed/segmented/divided into a plurality of components, eachcomponent of the plurality of components having a bandwidth that issmaller than the bandwidth of the signal. Accordingly, a transmitter maybe configured with a corresponding plurality of antennas and/or acorresponding plurality of other elements to transmit the plurality ofcomponents. Analogous operations for reception may be included in areceiver.

It will be understood that an element of said second matrix may bereal-valued, imaginary-valued or complex-valued. Further, it will beunderstood that, in some embodiments, a magnitude/amplitude remainssubstantially invariant in going from element-to-element of said secondmatrix, while a phase changes in going from element-to-element of saidsecond matrix, and that, in such embodiments, it is a pseudo-randomvariation of said phase that changes from element-to-element of saidsecond matrix, that is used to provide said scrambling. It will also beunderstood that in some embodiments wherein a transmitter is configuredto use said second matrix (alone or in combination with said firstmatrix), to scramble and transmit one or more data vectors, a receivermay be configured so as to know said second matrix in order todescramble the one or more scrambled data vectors that it receives fromsaid transmitter.

Still referring to the bottom trace of FIG. 12, a receiver may beconfigured to receive a time-domain version of a vector signal (e.g.,AC′), comprising at least one data element and at least one pilotsymbol, via an antenna (that may comprise a plurality of antennaelements), amplify the time-domain version of the vector signal via oneor more Low Noise Amplifiers (LNAs), sample the amplified time-domainversion of the vector signal via one or more samplers (thus generating adiscrete-time signal {x_(n)}; wherein the subscript “n” denotes discretetime and is to be distinguished from the vector n which denotes noise)and perform a Fourier transform on {x_(n)}; wherein the Fouriertransform that is performed on {x_(n)} is denoted as FFT(R) in FIG. 12;“(R)” for Receiver; and wherein the FFT(R) may be a Fast FourierTransform. An output of the FFT(R) may be used to provide a measure ofthe at least one pilot symbol which may be processed to derive anestimate of the channel matrix. The estimate of the channel matrix maythen be used to equalize the at least one data element of the receivedvector signal. Subsequent to the equalization, the equalized vectorsignal, minus the at least one pilot symbol thereof, may be subjected toan inverse Fourier transform, which may be an Inverse Fast FourierTransform, denoted as IFFT in FIG. 12, yielding an estimate of the datavector C of the top trace of FIG. 12.

It will be understood that the channel matrix that is estimated by thereceiver and used for said equalization of the received vector signalmay also be relayed by the receiver to the transmitter. It will also beunderstood that relaying an estimate of the channel matrix from thereceiver to the transmitter may comprise relaying an “up” or “down”command/increment wherein the transmitter, based upon an initialestimate of the channel matrix, uses the up or down command/increment toupdate said initial estimate of the channel matrix. It will further beunderstood that the up or down command/increment may relate to a realcomponent, an imaginary component, an in-phase component, a quadraturecomponent, a magnitude/amplitude and/or a phase of an element of thechannel matrix, and that, in some embodiments, a plurality of up or downcommands/increments may be relayed from the receiver to the transmitterin order to accommodate a respective plurality of elements of thechannel matrix.

It will be understood that the bottom trace of FIG. 12 illustrates anembodiment wherein an estimate of the channel matrix is known by thetransmitter and is used by the transmitter to pre-distort AC′, prior totransmission thereof, in order to compensate at least partially (i.e.,to pre-compensate at least partially) a channel distortion, such as, forexample, fading. However, a channel matrix represents a transmissioncharacteristic between a transmitter and a receiver, as is illustratedby the bottom trace of FIG. 12, and in embodiments where a transmitterneeds to serve a plurality of receivers, there is a correspondingplurality of channel matrices, each one of which is associated with arespective one of the receivers. Accordingly, in such embodiments, thetransmitter may be configured to sequentially, in time, communicate withthe plurality of receivers such that over a first time interval 0<t≦τ₁the transmitter is communicating only with a first receiver, over asecond time interval τ₁<t≦τ₂ the transmitter is communicating only witha second receiver, etc. Accordingly, over the first time interval thetransmitter may use an estimate of a channel matrix that relates to atransmission characteristic and/or response between the transmitter andthe first receiver, and over the second time interval the transmittermay use an estimate of a channel matrix that relates to a transmissioncharacteristic and/or response between the transmitter and the secondreceiver.

Accordingly, in some embodiments, a Base Transceiver Station (BTS)and/or a sector thereof, that may be of any physical structure and/orsize, and may be fixed, transportable and/or mobile, may be configuredto only transmit information (data, voice, signaling, pilot signals,etc.) to a first transceiver over a portion of a first time interval, toonly receive information (data, voice, signaling, pilot signals, etc.)from the first transceiver over a portion of the first time interval, toonly transmit information (data, voice, signaling, pilot signals, etc.)to a second transceiver over a portion of a second time interval and toonly receive information (data, voice, signaling, pilot signals, etc.)from the second transceiver over a portion of the second time interval;wherein the first and second time intervals do not overlap therebetween.It will be appreciated that over at least a portion of an i^(th) timeinterval (τ_(i-1)<t≦τ_(i)) the BTS and/or the i^(th) transceiver may usean entire available frequency space/channel owing to all othertransceivers associated with the BTS not using any time/frequencyresources during the i^(th) time interval. FIG. 14 illustratessystems/methods based on the above, wherein communications (includingdata, voice, signaling, pilot signals, etc.) between a BTS and/or asector thereof and a plurality of transceivers (e.g., mobile terminals,transportable terminals, fixed terminals, terminals installed onvehicles, etc.) occur sequentially in time over a respective pluralityof non-overlapping (e.g., mutually exclusive) time intervals.

According to further embodiments of the present invention, a BTS may beconfigured such that its sectors take turns in transmitting overmutually exclusive time intervals, as is illustrated in FIG. 15 a. Insome embodiments, at least two sectors of the BTS are configured toreceive simultaneously in order to maximize signal energy at the BTSfrom a transmitting transceiver (e.g., mobile terminal). It will beunderstood that a BTS, such as that illustrated in FIG. 14 and/or FIG.15 a, may be configured to provide service based upon a Time DivisionDuplex (TDD) protocol and/or a Frequency Division Duplex (FDD) protocol(such as, for example, WiFi, WiMAX, UMB and/or LTE).

In yet other embodiments of the invention, as illustrated in FIG. 16, afirst cluster of BTS (Cluster 1), comprising a number of Ω≧1 BTSs and atleast one transceiver (a radioterminal) that is communicating therewith(not illustrated in FIG. 16), communicate over a first time interval(0<t≦α_(Ω)) while at least one other cluster of BTS (including at leastone transceiver/radioterminal that is communicating therewith; e.g.,Cluster 2 and/or Cluster 3; see FIG. 16) that is/are adjacent and/orproximate to the first cluster of BTS remains silent (i.e., remainsdevoid of transmissions) during the first time interval. Furthermore, asis illustrated in FIG. 16, Cluster 4 and/or Cluster 5, beinggeographically distant from Cluster 1, may be configured to providecommunications (i.e., to radiate waveforms) concurrently with Cluster 1,using at least some of the spectrum that is also used by Cluster 1,while avoiding harmful interference with Cluster 1 owing to said beinggeographically distant relative to Cluster 1.

Still referring to FIG. 16, after Clusters 1, 4 and 5 have providedtheir respective communications over the time interval 0<t≦α_(Ω),Cluster 2 (and other Clusters associated therewith not shown) providetheir respective communications over a time interval, such as, forexample, α_(Ω)<t≦α_(2Ω), as is illustrated in FIG. 16. Similarly, afterClusters 1, 4 and 5 have provided their respective communications overthe time interval 0<t≦α_(Ω) and after Cluster 2 (and the other Clustersrelating to Cluster 2 not shown) provide their respective communicationsover the time interval α_(n)<t≦α_(Ω), Cluster 3 (and other Clustersassociated therewith not shown) provide their respective communicationsover a time interval, such as, for example, α_(2Ω)<t≦α_(3Ω), as isillustrated in FIG. 16. It will be understood that a number ofradioterminals per Cluster and a number of BTSs per Cluster may varyfrom Cluster-to-Cluster and that a time interval that is allocated to aCluster for the provision of communications may vary fromCluster-to-Cluster. Further, it will be understood that FIG. 16 is onlyillustrative, that shapes of clusters other than those illustrated inFIG. 16 may be provided and that frequency reuse distances other thanwhat is illustrated in FIG. 16 may be provided.

According to some embodiments, a time interval that is allocated to aCluster and/or a particular BTS for the provision of communications maydepend upon a number of wireless transceivers (i.e., wireless/mobileterminals) that are engaged in communications within the Cluster and/orthe particular BTS. In some embodiments, as a time interval that isallocated to a first Cluster and/or BTS for the provision ofcommunications increases, a time interval that is allocated to anotherCluster that may be adjacent and/or proximate to the first Clusterdecreases in order to maintain substantially invariant a periodicityassociated with providing an opportunity for communications.

In further embodiments of the invention, a BTS may comprise an evennumber of sectors (e.g., four sectors), as is illustrated, for example,in FIG. 15 a, and the data vector B may be transmitted/radiated over,for example, sector 1 while the data vector R is transmitter/radiatedsubstantially concurrently with the data vector B over substantially anopposite sector, such as, for example, sector 3; wherein at least someof the remaining sectors (i.e., sectors 2 and 4) are keptsilent/inactive; as is illustrated in FIG. 5 b. Upon havingtransmitted/radiated B and R substantially concurrently, as describedabove, and having received at the BTS any responses/transmissions fromrespective transceivers (mobile terminals), sectors 1 and 3 may gosilent/inactive (in terms of transmitting) while sectors 2 and 4 maybecome active (sectors 1 and 3 may remain active in terms of receiving).In these further embodiments of the invention, B and R may bestatistically independent and/or uncorrelated therebetween (i.e., atleast some data included in B may be independent/uncorrelated to atleast some data included in R) and/or B and R may be congruent in afrequency space (e.g., data elements/sub-carriers of R may not beshifted in frequency relative to data elements/sub-carriers of B).Accordingly, frequency reuse may take place between, for example, sector1 and sector 3 (e.g., between substantially opposite sectors of a BTS),as is illustrated in FIG. 15 b. A sequence of transmissions activitybetween different BTSs may remain as described earlier or may bemodified so that sectors radiating in substantially non-interferingdirections are allowed transmissions activity concurrently with sectors1 and 3 (or sectors 2 and 4) of the BTS of FIG. 15 b. Accordingly,significant spatial isolation may advantageously be relied upon toconduct receiver processing as described earlier in reference to FIG. 4a and/or FIG. 5 a. It will be understood that, in some embodiments, BTSsectors that are specified as “silent/inactive” are silent/inactive onlyin that they refrain from transmitting. Such sectors may remain activein terms of receiving.

In yet further embodiments, a transceiver (e.g., a mobile terminal) thatis communicating with a BTS may be configured to radiate informationbased upon a single carrier (as opposed to using a plurality ofcarriers/sub-carriers as in OFDM) in order to limit a peak-to-averagepower ratio of a waveform that is being amplified by an amplifier priorto transmission thereof. However, using a single carrier, instead of aplurality of carriers/sub-carriers, may require an equalizer at the BTSreceiver if the single carrier is sufficiently broadband. Alternatively,an equalizer at the BTS receiver may not be necessary if the singlecarrier is sufficiently narrowband. However, limiting the single carrierto a sufficiently narrow bandwidth also limits a data throughput fromthe transceiver to the BTS. Accordingly, in some embodiments, thetransceiver is configured to include a plurality of amplifiers, thusallowing a respective plurality of carriers/sub-carriers to be formed bythe transceiver and be distributed over the plurality of amplifiers suchthat any one of the plurality of amplifiers amplifies a number ofcarriers/sub-carriers that is less than the plurality ofcarriers/sub-carriers. In some embodiments, each one of the amplifiersof the plurality of amplifiers is amplifying a singlecarrier/sub-carrier.

A respective plurality of outputs of the plurality of amplifiers may becombined therebetween and used to excite an antenna of the transceiver,a subset of the respective plurality of outputs may be combinedtherebetween and used to excite an antenna of the transceiver and/or asingle output of the respective plurality of outputs may be used byitself to excite an antenna of the transceiver. In some embodiments, thetransceiver is configured with a respective plurality of antennaswherein each antenna of the respective plurality of antennas is excitedby a single output of the respective plurality of outputs of theplurality of amplifiers. In further embodiments, the plurality ofamplifiers may be arranged in accordance with a Butler matrixarchitecture. It will be understood that the transceiver may be a mobileterminal, a BTS or any other device that may be mobile, transportable,fixed, localized, distributed in space, installed in/on a vehicle, etc.It will also be understood that at least two antennas of the respectiveplurality of antennas may be spaced apart therebetween or may besubstantially co-located therebetween.

In yet further embodiments of the invention, N antennas are provided(N≧2), each being excited by, and/or radiating, one N^(th) of a totalsignal power (that may, otherwise, have been radiated by a singleantenna, or that may otherwise have been used to excite the singleantenna). In addition to the above, in some embodiments of theinvention, a signal that is used to excite an i^(th) antenna (or asignal that is being radiated by the i^(th) antenna; i=1, 2, . . . , N)is multiplied by an inverse of a channel response, 1/h_(i) (or by anyother function of the channel response) that relates to a propagationcharacteristic between the i^(th) antenna and an antenna of atransceiver/terminal, that may be a mobile terminal, that is receiving,as is illustrated in FIG. 17. It will be understood that if the channelresponse and/or propagation characteristic is frequency selective over abandwidth of B, then the channel response and/or propagationcharacteristic may be represented by a matrix (which may include complexelements and may be a diagonal matrix) instead of a scalar (which may bea complex scalar), as those skilled in the art will appreciate. Subjectto the above, it may be appreciated that a signal-to-noise ratio (and/ora signal-to-interference ratio) at the mobile terminal increases by afactor of N relative to having used a single antenna at the BTS totransmit to the mobile terminal. As those skilled in the art willappreciate, this is a result of N desired signal replicas arriving atthe mobile terminal coherently and adding in-phase, on a voltage basis,while the noise/interference variance at the mobile terminal remainsinvariant, at σ². It will be understood that although the BTS antennasof FIG. 17 are illustrated as transmitting, one or more of theseantennas may also be configured to receive and, in some embodiments, atleast two of these antennas may be substantially collocated. Further, itwill be understood that although a single mobile terminal antenna isillustrated in FIG. 17, two or more mobile terminal antennas may beprovided, in some embodiments, and that the two or more mobile terminalantennas may be substantially collocated. Additionally, it will beunderstood that although FIG. 17 illustrates a specific powerdistribution across the N antennas, any other power distribution acrossthe N antennas may be provided in other embodiments. Also, incalculating (S/N), FIG. 17 assumes that |B|=1, but this need not be thecase in general (wherein |•| denotes magnitude of “•”).

The embodiment illustrated in FIG. 17 suggests that the BTS serves eachone of a plurality of mobile terminals sequentially, overnon-overlapping time intervals (as discussed earlier), since differentchannel responses would generally apply between the BTS and differentmobile terminals. Accordingly, FIG. 17 suggests a broadband embodimentwherein a significant amount of spectrum is available (e.g., an amountof spectrum that is greater than, or equal to, 50 MHz and, in someembodiments, an amount of spectrum that is greater than, or equal to,100 MHz) in order to sequentially serve different mobiles within a BTSsector, different sectors of the same BTS, different BTSs (up to 3 or 4,or more) of a BTS cluster and/or different BTS clusters, as describedearlier in reference to FIGS. 14-16, while maintaining a throughputrelative to any mobile at, or above, a desired threshold, andmaintaining interference at, or below, a desired limit. It will beunderstood that in some embodiments, first and second groups of mobiles,first and second groups of sectors of a BTS, first and second BTSs of aBTS cluster and/or first and second BTS clusters may be served viarespective different first and second sets of frequencies which may benon-overlapping and mutually exclusive therebetween. In suchembodiments, the first and second groups of mobiles, the first andsecond groups of sectors of a BTS, the first and second BTSs of a BTScluster and/or the first and second BTS clusters that communicate viathe respective different first and second sets of frequencies maycommunicate concurrently without incurring harmful interference. In someembodiments, the respective different first and second sets offrequencies are provided, at least partially, by respective differentfirst and second entities; wherein the first entity and/or the secondentity is a wireless service provider, commercial entity, not for profitentity and/or government entity; so as to share the BTS and/or otherwireless network infrastructure.

It will be understood that any of the embodiments described herein (orany element/portion of any embodiment described herein) may be combinedwith any other embodiment described herein (or element/portion thereof)to provide yet another embodiment. This is stated for clarity of scopeof the invention since the number of different embodiments that areprovided by the present invention are too numerous to list and describeindividually and in whole. For example, elements of the embodiment ofFIG. 17 may be combined with elements of the embodiment of FIG. 15 b toprovide yet another embodiment wherein first and second sectors of a BTSeach comprises a plurality of radiating antenna elements and wherein thefirst sector is configured to radiate waveforms in a first directionbased upon B over a time interval and wherein the second sector isconfigured to radiate waveforms in a second direction, that issubstantially opposite to the first direction, based upon R oversubstantially the same time interval.

We observe that in the future, many devices will be wirelessly connectedtherebetween and will be configured to communicate therebetweenfrequently and quite transparently (i.e., without active/explicit humanintervention). We also observe that as knowledge increases and as moreand more applications for the knowledge are identified (presumably andhopefully for the benefit of humanity) a level of communications betweendevices will increase. Accordingly, any embodiment of any invention thatmay be used to increase wireless communications capacity may prove ofsignificant value. For example, it is envisaged that in the future aperson (in cooperation with his/her doctor) may have an option to befitted with a sensing/dispensing device that may be configured tosense/detect/estimate a state of a biological function/parameter of theperson, such as, for example, a heart function/rate, a bloodstate/pressure, a blood sugar level, a blood oxygen level, a mentalstate, etc. and the sensing/dispensing device may also be configured tocommunicate wirelessly with at least one predetermined second device. Insome embodiments, the sensing/dispensing device may be configured tocommunicate wirelessly with a predetermined device of the person suchas, for example, a wireless communications device of the person (e.g., amobile phone of the person) and/or with any other device of the personand/or of another person who may be associated with the person (e.g., aperson's spouse, parent, guardian, employer, medicalprovider/doctor/nurse, etc.).

The sensing/dispensing device may be configured to communicate with theat least one predetermined second device over a wireless link, that maybe a short-range wireless link, such as, for example, a Bluetooth link,wherein the wireless link may be a bi-directional wireless link, and torelay data to the at least one predetermined second device. The at leastone predetermined second device, that may be a wireless communicationsdevice of the person (e.g., a mobile phone of the person), may beconfigured to communicate information to a medical facility/CPU/doctorin response to having received from the sensing/dispensing device dataindicating an “out-of-limits” and/or “marginal” reading associated withthe person. Accordingly, the medical facility/CPU/doctor may beinformed, in substantially real time, of a state of health of the personand an appropriate response may then be relayed back to the person via,for example, the wireless communications device of the person and to thesensing/dispensing device of the person via the wireless link betweenthe wireless communications device of the person and thesensing/dispensing device. Accordingly, the sensing/dispensing devicemay be configured to dispense a substance to the person in order toremedy the out-of-limits and/or marginal reading. Thus, substantiallyreal-time closed-loop feedback control, using wireless communications,may be provided to regulate a medical state/condition of the person.According to some applications, the regulation of the medicalstate/condition of the person may be automatic and substantiallytransparent to the person (i.e., without any cognizant intervention onthe part of the person). In other applications, an intervention/actionby the person, such as an authorization/approval by the person, may berequired prior to dispensing of the substance by the sensing and/ordispensing device.

In further applications, each one of a plurality of home/office devices(such as, for example, a vehicle, a garage door opener, an electricalsystem, a power meter, a refrigerator, an air conditioner, a heatingsystem, a television/entertainment unit, an alarm system, etc.) may bewirelessly connected, via a respective plurality of wireless links, thatmay be short-range wireless links, to a transceiver unit that may beinstalled within the home/office. The transceiver unit may be configuredto communicate wirelessly with at least one other transceiver unit thatmay be associated with another home/office and may also be configured tocommunicate wirelessly, via a terrestrial base station and/or via asatellite, with one or more service provider facilities. Accordingly,the transceiver unit may receive information, such as state/diagnosticinformation, from each one of the plurality of home/office devices and,responsive to an undesirable state/diagnostic, the transceiver unit mayinform the other transceiver unit and/or at least one relevant serviceprovider facility of the undesirable state/diagnostic. Accordingly, anappropriate response may be provided by the at least one relevantservice provider and/or by the other transceiver unit in order tocorrect the undesirable state/diagnostic. In some embodiments, thetransceiver unit may also be configured to communicate with a device,such as a mobile device, of an occupant and/or owner of the home/officeresponsive to the undesirable state/diagnostic. It will be understoodthat the transceiver unit may, in some embodiments, be integrated withina computer and/or connected to the computer and that the transceiverunit may be configured to communicate with the at least one othertransceiver unit and/or the one or more service provider facilities viathe computer using at least one wireline link (cable, DSL, ADSL, fiberoptical, etc.) and/or at least one wireless link (terrestrial,satellite, etc.).

In yet additional applications, a mobile device (such as a mobilephone/terminal) may be configured to conduct communications autonomouslyand without an intervention (i.e., cognizant intervention) by a user ofthe mobile device. The communications that may be conducted by themobile device autonomously and without the intervention may be inresponse to a predetermined Time-of-Day (ToD), Time-of-Month (ToM),Time-of-Year (ToY), Time of Decade (ToD) and/or Time-of-Century (ToC).Further, the communications that may be conducted by the mobile deviceautonomously and without the intervention may be in response to apredetermined distance of the mobile device relative to a predeterminedlocation/entity (stationary or not), a sensing of the mobile device of apredetermined signal and/or a characteristic thereof, a health state ofthe user of the mobile device, a noise/sound level in the vicinity ofthe mobile device, an acceleration of the mobile device, amunicipal/city/state/national emergency and/or a time lapse relative toa predetermined point in time. It will be understood that thecommunications that may be conducted by the mobile device autonomouslyand without the intervention may be first communications responsive to afirst one of a predetermined Time-of-Day (ToD), Time-of-Month (ToM),Time-of-Year (ToY), Time of Decade (ToD), Time-of-Century (ToC), apredetermined distance of the mobile device relative to a predeterminedlocation/entity (stationary or not), a sensing of the mobile device of apredetermined signal and/or a characteristic thereof, a health state ofthe user of the mobile device, a noise/sound level in the vicinity ofthe mobile device, an acceleration of the mobile device, amunicipal/city/state/national emergency and a time lapse relative to apredetermined point in time; and a second communications responsive to asecond one of a predetermined Time-of-Day (ToD), Time-of-Month (ToM),Time-of-Year (ToY), Time of Decade (ToD), Time-of-Century (ToC), apredetermined distance of the mobile device relative to a predeterminedlocation/entity (stationary or not), a sensing of the mobile device of apredetermined signal and/or a characteristic thereof, a health state ofthe user of the mobile device, a noise/sound level in the vicinity ofthe mobile device, an acceleration of the mobile device, amunicipal/city/state/national emergency and a time lapse relative to apredetermined point in time; wherein the first communications may differfrom the second communications. In some applications, the mobile devicemay be configured to conduct the communications autonomously and withoutthe intervention even though the mobile device has been placed in anoff/inactive mode (e.g., has been turned off) and/or even though abattery of the mobile device has been removed from the mobile device(e.g., the mobile device may include a reserve of power that is separatefrom the battery of the mobile device). In further embodiments, themobile device may be configured to detect a proximity state betweenitself and a television/computer and, responsive to the detectedproximity state to wirelessly transfer data (e.g., at least one contentthereof) to the television/computer (and, in some embodiments, viceversa). The television/computer may be a predeterminedtelevision/computer and the proximity state may be detected byestimating a distance between the mobile device and saidtelevision/computer and/or by sensing a signal and/or a characteristicthereof.

Accordingly, it may be appreciated that at least some of the aboveapplications, as well as other numerous applications that may occur tothose skilled in the art, may be practiced in the future, requiringadditional capacity from wireless networks.

In further embodiments of the present invention, a system/method isprovided (that may be a system/method associated with a receiver and/ora transmitter) that includes a spatial rake. A system/method comprisinga spatial rake may improve a signal-to-noise ratio and/or asignal-to-interference ratio and, according to some embodiments, mayallow reuse of available radio resources even within a sector of a basestation and/or over adjacent sectors of the base station (i.e.,co-sector and/or adjacent sector co-channel operation). The well-knownrake receiver that is practiced in Code Division Multiplexed (CDM)and/or Code Division Multiple Access (CDMA) wireless communicationssystems/methods may be viewed as a receiver that rakes-in (i.e.,gathers/accumulates) a plurality of replicas of a CDM/CDMA signal;wherein the plurality of replicas are dispersed in time and areresolvable in time. Analogously, a spatial rake may be provided thatrakes-in a plurality of replicas of a signal that are dispersed in spaceand are resolvable in space. As may be appreciated by those skilled inthe art, multipath propagation provides a plurality of signal paths,from a transmitter to a receiver, with each path of the plurality ofpaths characterized by a magnitude (i.e., signal strength) and an angleof arrival; see FIG. 18 a. Accordingly, a receiver, comprising aplurality of antenna elements, may be configured to form an antennapattern, using the plurality of antenna elements, that is optimally (ornear optimally) matched to the plurality of signal paths in terms ofamplitude (signal strength/gain) and angle of arrival. FIG. 18 billustrates a plurality of signal paths (as in FIG. 18 a), comprisingthree signal paths, and an associated antenna pattern that is matched tothe plurality of signal paths. Accordingly, a signal-to-noise ratioand/or a signal-to-interference ratio may be improved, improving acommunications performance index such as, for example, a link capacity,a Bit Error Rate (BER), a Quality of Service (QoS), etc.

A receiver, as illustrated in FIG. 19 a, may include the plurality ofantenna elements and a first processor, labeled as signal processor 1 inFIG. 19 a, that processes a respective plurality of signals, provided tothe signal processor 1 by the plurality of antenna elements, to form aplurality of antenna patterns (sequentially in time and/or in parallelin time; depending on a speed of operation of the processor). Each oneof the plurality of antenna patterns, also referred to herein as lobes,pencil beams and/or spatial fingers (or simply fingers), may beassociated with a respective angle of arrival and may be used by theprocessor to provide a respective signal strength measure. Therespective signal strength measure may be determined by processing oneor more pilot signals via a respective antenna pattern (i.e.,lobe/finger/pencil beam) of the plurality of antenna patterns.Accordingly, the plurality of antenna patterns that may be formed by theprocessor, providing a respective plurality of signal strength measurescorresponding to a respective plurality of angles of arrival spanning apredetermined interval of space, may be used by the processor todetermine/estimate an antenna pattern that is spatially matched (ornearly/approximately spatially matched) to the plurality of signal paths(as illustrated in FIG. 18 a and/or in FIG. 18 b) arriving at thereceiver.

According to some embodiments, as illustrated in FIG. 19 a, a receivermay be configured to form a set of signal samples by sampling an outputof each one of the plurality of antenna elements, to store the set ofsignal samples in memory, to provide at least a subset of the set ofsignal samples to the signal processor 1 (e.g., samples that may beassociated with the one or more pilot symbols) so that the signalprocessor 1 may form the plurality of antenna patterns(lobes/fingers/pencil beams), as discussed above, and determinetherefrom the respective plurality of signal strength measures; and,after the processor has estimated an antenna pattern that is spatiallymatched (or nearly spatially matched) to the plurality of signal paths,responsive to the processor having formed the plurality of antennapatterns, to use the spatially matched (or nearly spatially matched)antenna pattern to process the set of signal samples (or a subsetthereof comprising data samples and/or pilot samples) and to provide anoutput of the spatially matched antenna pattern to a second processor,labeled as signal processor 2 in FIG. 19 a, in order to detect data.FIG. 19 b provides illustrative additional detail of the receiver thatis illustrated in FIG. 19 a, for some embodiments.

In further embodiments of the invention, the receiver that has beendescribed above, as illustrated in FIG. 19 a and/or in FIG. 19 b, mayfurther be configured to detect/estimate a correlation between first andsecond signals (that may be first and second pilot signals), that arereceived at respective first and second antenna elements of theplurality of antenna elements. Responsive to the detected/estimatedcorrelation between the first and second signals (and in someembodiments responsive to a detected/estimated correlation between thefirst and second signals and between at least two more signals) thereceiver may be configured to preferentially use signal outputs of atleast some of the plurality of antenna elements to perform signalprocessing that is different than the spatial matched filteringdiscussed above and illustrated in FIG. 19 a and/or in FIG. 19 b.Accordingly, in some embodiments, the receiver may be equipped with aplurality of different signal processing algorithms and the receiver maybe equipped/configured with adaptivity/agility so as to preferentiallyuse one algorithm of the plurality of algorithms vs. another algorithmof the plurality of algorithms responsive to a value of saiddetected/estimated correlation (or any other signal property) betweenthe first and second signals (and in some embodiments responsive to adetected/estimated correlation and/or other signal property between thefirst and second signals and between at least two more signals).

In some embodiments, the receiver may be configured to process a firstset of signals, associated with a respective first set of antennaelements, via a first signal processing algorithm and to process asecond set of signals, associated with a respective second set ofantenna elements, via a second signal processing algorithm. It will beunderstood that the first signal processing algorithm may differ from,or be the same as, the second signal processing algorithm and that atleast one (and, in some embodiments, each one) of the first and secondsets of antenna elements may be a subset of the plurality of antennaelements. It will also be understood that the first and second sets ofantenna elements may be intersecting or non-intersecting therebetween.In some embodiments, the first signal processing algorithm comprisesspatial matched filtering and the second signal processing algorithmalso comprises spatial matched filtering.

Accordingly, in some embodiments of the invention, if said correlationand/or other signal property is greater than or equal to a predeterminedthreshold, the receiver is configured to utilize signal outputs of atleast some of the plurality of antenna elements in accordance with afirst signal processing algorithm and if said correlation and/or othersignal property is less than the predetermined threshold, the receiveris configured to utilize signal outputs of at least some of theplurality of antenna elements in accordance with a second signalprocessing algorithm that is different than the first signal processingalgorithm. In yet further embodiments, the receiver may be configured toutilize signal outputs of at least some of the plurality of antennaelements in accordance with a third (hybrid) algorithm that comprises atleast one aspect/element of the first algorithm and at least oneaspect/element of the second algorithm. The third (hybrid) algorithm maybe used over a transition interval wherein said correlation and/or othersignal property is greater than a lower threshold but less than an upperthreshold.

Accordingly, in such embodiments, if said correlation and/or othersignal property is greater than or equal to the upper threshold, thereceiver is configured to utilize signal outputs of at least some of theplurality of antenna elements in accordance with the first signalprocessing algorithm, if said correlation and/or other signal propertyis less than or equal to the lower threshold, the receiver is configuredto utilize signal outputs of at least some of the plurality of antennaelements in accordance with the second signal processing algorithm andif said correlation and/or other signal property is between the lowerand upper thresholds, the receiver is configured to utilize signaloutputs of at least some of the plurality of antenna elements inaccordance with the third (hybrid) signal processing algorithm. In someembodiments, the first algorithm may comprise spatial matched filtering,as is, for example, described above and illustrated in FIG. 19 a and/orin FIG. 19 b, and wherein the second algorithm may be devoid of spatialmatched filtering and comprise, for example, a Multiple Input MultipleOutput (MIMO) algorithm, equalization/rake and/or diversity combining ofsignal outputs of at least some of the plurality of antenna elements. Itwill be understood that the term “equalization” as used herein maycomprise one or more transversal filters (synchronously and/orfractionally spaced with or without decision feedback) and the term“diversity combining” may comprise maximal ratio combining or any othertype of combining (linear and/or non-linear) of signal outputs of atleast some of the plurality of antenna elements, in some embodiments. Infurther embodiments, the second algorithm may also comprise spatialmatched filtering.

In additional embodiments, instead of the above, or in combination withany aspect(s) of the above, the receiver may be equipped with aplurality of different signal processing algorithms and the receiver maybe configured to provide communications to a first terminal bypreferentially using one algorithm (i.e., a first algorithm) of theplurality of algorithms while avoiding/refraining from using any otheralgorithm of the plurality of algorithms, to provide communications tothe first terminal, responsive to a location of the first terminaland/or responsive to a location of a second terminal which, according tosome embodiments, the receiver may be serving (currently and/or in thefuture) using radio resources that are co-channel with radio resourcesthat the receiver is using (or is about to use) to serve the firstterminal. In yet other embodiments of the invention, instead of theabove, or in combination with any aspect(s) of the above, the receivermay be equipped with a plurality of different signal processingalgorithms and the receiver may be configured to provide communicationsto a terminal by preferentially using one particular/specific algorithmof the plurality of algorithms while refraining from using any otheralgorithm of the plurality of algorithms, to provide communications tothe terminal, responsive to one or more channel characteristics thatexist between the terminal and one or more of the receiver's antennaelements. In further embodiments, however, all algorithms of theplurality of different signal processing algorithms may beallowed/enabled/activated to function substantially concurrently and/orindependently therebetween providing a respective plurality of outputs.A first output of the plurality of outputs may be given preferentialweight over at least one other output of the plurality of outputs andthe first output of the plurality of outputs may, accordingly, be usedfor recovering data, based upon (e.g., responsive to), for example, asignal-to-interference/noise ratio, a bit error-rate and/or any othermeasure thereof.

It will be understood that even thought in FIG. 19 b, and/or in any ofthe other Figures relating to the present invention, an arrow may beillustrated as providing a unidirectional (i.e., one directional)connection/path, such an arrow may, according to some embodiments, be abi-directional arrow providing a bi-directional connection/path (or aconnection/path in a direction opposite to that illustrated). Forexample, a system/method/device that may be illustrated in one or moreFigures of the present specification may relate to a receiver and mayalso relate to a transmitter (i.e., may relate to a transceiver), asthose skilled in the art will appreciate. Accordingly, for the receiverpart, for example, one or more arrows may be illustrated as providingone or more respective paths/connections from an antenna of the receiverto one or more other element(s) of the receiver. For the transmitterpart, however, in some embodiments, the one or more paths/connectionsmay have to be reversed in a direction thereof. As may be appreciated bythose skilled in the art, in some embodiments, information attained bythe receiver may have to be “turned-around” and used by at least oneelement of the transmitter.

FIG. 20 illustrates a receiver that is providing communications,concurrently and co-channel, to two terminals (not shown), referred toin FIG. 20 as terminal 1 and terminal 2. The receiver that isillustrated in FIG. 20 has detected a relatively high correlation and/orother signal property across at least some of its antenna elements forsignals relating to terminal 1 and for signals relating to terminal 2.Accordingly, the receiver has determined that each one of the twoterminals (terminal 1 and terminal 2) is associated with at least someresolvable signal paths (as illustrated in FIG. 18 a, FIG. 18 b, FIG. 19a and/or FIG. 19 b) and that the two terminals are sufficiently spacedapart therebetween so as to be served concurrently and co-channel using(for each one of the two terminals) spatial matched filtering,equalization/rake and/or interference reduction. It will be understoodthat if terminal 1 and terminal 2 are configured to communicate usingOFDM/OFDMA signals, the equalizer/rake stage of the receiver of FIG. 20may not be needed. Further, it will be understood that two differentantenna systems, each comprising a plurality (e.g., N≧2) of antennaelements may be used to provide signal inputs to the spatial matchedfilter coefficients {W₁₁, W₂₁, . . . , W_(N1)} and coefficients {W₁₂,W₂₂, . . . , W_(N2)}, respectively, instead of the single antennasystem, comprising the plurality of (N≧2) antenna elements, asillustrated in FIG. 20.

Although in FIG. 20 only one signal path is illustrated as arriving fromterminal 1, only one signal path is illustrated as arriving fromterminal 2 and the two respective signal paths from terminal 1 andterminal 2 are illustrated in FIG. 20 as arriving from respectivesignificantly different directions, this need not be the case ingeneral. In some embodiments of the invention, a signal path (or aplurality of signal paths) from, for example, terminal 1 may be limitedto a first angle-of-arrival (or a limited/small/narrow continuum offirst angles of arrival) while a signal path (or a plurality of signalpaths) from terminal 2 may comprise a plurality of second angles ofarrival (or a relatively broad/large/wide continuum of second angles ofarrival), and the plurality of second angles of arrival may comprise anintersection/overlap with the first angle of arrival, as is illustratedin FIG. 21. In some embodiments, a terminal determines/estimates aposition thereof, relays the determined/estimated position to a basestation, the base station uses the relayed position of the terminal and,in some embodiments, additional information regarding natural and/orman-made structures to form an antenna pattern, and uses the formedantenna pattern to conduct communications with the terminal.

In yet additional embodiments of the present invention, based on arealization that a large number of base station antenna elements maypreferably be used at a base station (or at a base station sector) toprovide improved communications performance, a base station architectureis provided, comprising electrical and structural/mechanical elements,as is illustrated in FIG. 22 and in FIG. 23, that is capable ofaccommodating the large number of base station antenna elements. It willbe appreciated by those skilled in the art, that providing at least twovertical structural/mechanical support posts (as is illustrated in FIG.22), on which at least one horizontal structural post may be mounted andused to support a plurality (N≧2) of antenna elements, the plurality(N≧2) of antenna elements may be structurally more sound (and an overallstructure of a base station tower may be structurally more sound)allowing the number N of antenna elements to increase. Accordingly, abase station that is based upon an architecture as described above andillustrated in FIG. 22 and FIG. 23 may provide improved communicationsperformance. It will be understood that two or more sectors of the basestation may be based upon the architecture described above.

Accordingly, in some embodiments, as a number of antenna elements of abase station is increases in order to provide improved communicationsperformance, an increase in a number of cables may need to be providedbetween a base/foundation of the base station and the number of antennaelements that are configured on (e.g., at or near the top of) a tower ofthe base station. For example, if the base station comprises threesectors and each one of the three sectors is based upon an architectureas illustrated in FIG. 22 with, for example, sixteen antenna elements(N=16), then a total of 48 cables may have to be provided between thebase/foundation and the plurality (forty eight) of antenna elements. Insome embodiments, the vertical structural support posts illustrated inFIG. 22 and in FIG. 23 may be hollow and at least some of the cables maybe configured inside of the hollow vertical structural support posts. Infurther embodiments, however, instead of cables (or in combination withat least some cables) at least one wireless link, that may be configuredto be at least one short-range wireless link and, in some embodiments,at least one short-range wireless link that uses (is based upon) atleast one directional antenna, may be used to communicate informationbetween the base/foundation of the base station and the plurality ofantenna elements that are configured on the tower of the base station,as is illustrated in FIG. 22 and/or FIG. 23.

The at least one wireless link that may be used to communicateinformation between the base/foundation of the base station and theplurality of antenna elements that are configured on the tower of thebase station may be based upon any technology and/or protocol (such as,for example, Time Division Multiplexing (TDM) of a plurality of signals,Code Division Multiplexing (CDM) of the plurality of signals, OrthogonalFrequency Division Multiplexing (OFDM) of the plurality of signals,etc., or any combination thereof) and the multiplexor/demultiplexor thatis illustrated in FIG. 22 may be configured in accordance with thetechnology and/or protocol that is used. Further to the above, the atleast one wireless link that may be used to communicate informationbetween the base/foundation of the base station and the plurality ofantenna elements that are configured on the tower of the base stationmay be based upon any frequency band (licensed and/or unlicensed) and,according to some embodiments of the invention, the at least onewireless link may preferentially be based upon frequencies above GHzand, in further embodiments, above 20 GHz, in order to increase apropagation attenuation thereof, such as, for example, an atmosphericabsorption thereof, and thus limit a propagation distance thereof,reducing a level of potential interference.

It will be understood that although a single bi-directional wirelesslink is illustrated in FIG. 22, other embodiments may comprise aplurality of wireless links each one of which may be a short rangewireless link and bi-directional (transferring information up and downthe tower) or one-directional (transferring information either up ordown the tower). Further, each one of the plurality of wireless linksmay use (be based upon) at least one directional antenna in order tomaximize a radiation level thereof in a first predetermined direction(e.g., up and/or down; vertical direction) while minimizing, limitingand/or reducing a radiation level thereof in a second predetermineddirection (e.g., in a horizontal direction). In accordance with onespecific embodiment, two wireless links may be used wherein a first oneof the two wireless links is configured to transfer information from theantenna elements of the tower to the base/foundation of the base stationwhile a second one of the two wireless links is configured to transferinformation from the base/foundation of the base station to the antennaelements of the tower. In accordance with this one specific embodiment,the first wireless link may be preceded by at least one Low NoiseAmplifier (LNA), that may comprise a plurality of LNAs that may beconfigured in accordance with a Butler Matrix architecture; and thefirst wireless link may also be preceded by a multiplexor; an output ofthe at least one LNA being connected to an input of the multiplexor;both of which (the at least one LNA and the multiplexor) beingconfigured at a height from the base/foundation of the tower (e.g., atthe top of the tower, near the top of the tower and/or proximate to theantenna elements of the tower). Further, in accordance with said onespecific embodiment, the first wireless link may be followed by ademultiplexor and/or additional electronics that is configured at ornear the base/foundation of the tower

Continuing with said one specific embodiment, the second wireless linkmay be preceded by a multiplexor that is configured at (or near) thebase/foundation of the tower and the second wireless link may befollowed by a demultiplexor an output of which may be connected to aninput of a Power Amplifier (PA), that may comprise a plurality of PAsthat may be configured in accordance with a Butler Matrix architecture,at (or near) the top of the tower and/or proximate to one or moreantenna elements of the tower and configured to drive/excite the one ormore antenna elements of the tower that may comprise a plurality ofantenna elements as illustrated in FIG. 22 and/or in FIG. 23. Adimensionality of the Butler Matrix architecture may depend upon anumber of antenna elements of the tower; and a Butler Matrix of N×Ndimension may be used to drive N antenna elements of the tower.

In general, it will be understood that a multiplexor/demultiplexor mayinclude (or be connected to) at least one Low Noise Amplifier (LNA)and/or at least one Power Amplifier (PA) and that the at least one LNAand/or the at least one PA may be configured in accordance with a ButlerMatrix architecture, well known to those skilled in the art, in order toprovide an amplification redundancy and/or a graceful degradation ofperformance in the event that one or more amplifier failures occur (atleast one redundant amplifier may also be provided so that a redundantamplifier may be used (switched in) to replace a defective amplifier).The at least one PA may comprise a plurality of outputs that may be usedto drive/excite a respective plurality of antenna elements situated on atower of a base station; and the at least one LNA may comprise aplurality of inputs that may be used to receive and amplify a respectiveplurality of signals from a respective plurality of antenna elements.

It will be understood that each antenna element of the plurality ofantenna elements may comprise at least one dipole radiating element, atleast one monopole radiating element, at least one patch radiatingelement and/or any other radiating element such as, for example,waveguide opening(s), coaxial cable opening(s), etc. It will also beunderstood that each antenna element of the plurality of antennaelements may be linearly polarized (in at least one spatial dimension)and/or circularly polarized (left-hand circular or right-hand circular)and that different antenna elements may comprise different polarizationsand/or different mechanical/electrical characteristics therebetween.Further, it will be understood that although FIG. 22 illustrates only asingle row of N antenna elements that is used to form an overall antennaof a base station sector, a plurality of rows of antenna elements (ofequal or differing number of antenna elements therebetween) may beconfigured at a respective plurality of elevations on a base stationtower to thereby provide antenna beam steering capability along anelevation dimension. Accordingly, a two dimensional antenna array may beformed for a base station sector.

A two dimensional antenna array for a base station is illustrated inFIG. 24, in accordance with some embodiments, wherein a circular tubulararchitecture may be used that comprises a two-dimensional lattice ofantenna elements, as is illustrated in FIG. 24. According to otherembodiments, however, the architecture that comprises thetwo-dimensional lattice of antenna elements need not be circulartubular. FIG. 25, for example, illustrates a top view of a polygonalarchitecture according to some embodiments. The polygonal architecturemay comprise any desired number of sides, such as, for example, 3, 4, 5,etc.; and, as it may readily be observed, as the number of sides of thepolygonal architecture becomes very large (i.e., approaches infinity),the polygonal architecture approaches a circular tubular architecture,as has already been illustrated in FIG. 24. It will be understood thatalthough the architectures that are illustrated in FIG. 24 and in FIG.25 include only three vertical structural posts each, more than three(or less than three) vertical structural posts may be provided infurther embodiments. Furthermore, it will be understood that althoughhorizontal structural posts are not illustrated in FIG. 24 and FIG. 25,horizontal structural posts may also be provided in yet furtherembodiments. It will further be understood that any of the base stationtower architectures illustrated herein may be encapsulated, at leastpartially by a radome material for protection against the elements(weather) and/or for climate control.

Those skilled in the art will appreciate that any of the embodimentsdescribed herein (or any element/portion of any embodiment that isdescribed herein) may be combined with any other embodiment that isdescribed herein (or element/portion thereof) to provide yet anotherembodiment. For example, elements of the embodiment that are illustratedin FIG. 22 may be combined with elements of the embodiment that areillustrated in FIG. 24 and/or in FIG. 25 to provide at least one otherembodiment wherein a base station comprising a two-dimensional antennaarray uses one or more wireless links to transport information backand/or forth between the two-dimensional antenna array and a processingfacility associated with the base station. The processing facility maybe proximate to, attached to, connected to and/or integrated with abase/foundation of the tower of the base station, in some embodiments,as has been described earlier, or it may be at a distance from thebase/foundation of the tower of the base station, in other embodiments.

Accordingly, it is envisaged that, owing to an ever-increasing appetitefor wireless broadband communications by various world communities(human and/or machine), systems, methods, architectures, devices,software, firmware and/or computer programs that improve spectralefficiency and communications capacity will be introduced, according tovarious embodiments of the present invention and/or other inventions,even though a signal processing complexity thereof may, currently and/orin the future, appear prohibitive. As is well understood and appreciatedby those skilled in the art, anything that is associated withcomputationally prohibitive requirements today, in a decade or so willsurrender to Moore's Law.

In the present specification and figures (and in the references thathave been incorporated herein by reference in their entirety as if setforth fully herein), there have been disclosed embodiments of theinvention and, although specific terms are employed, they are used in ageneric and descriptive sense only and not for purposes of limitation;the following claims setting forth the scope of the present invention.

What is claimed is:
 1. A communications method comprising: configuring aplurality of transmitter chains; and transmitting an overall signal by amobile transmitter by using a first transmitter chain of the pluralityof transmitter chains and a second transmitter chain of the plurality oftransmitter chains to transmit respective first and second differentcomponents of the overall signal over respective first and secondmutually exclusive frequencies.
 2. The communications method accordingto claim 1, further comprising: exceeding by the overall signal a limitassociated with a subsystem of the mobile transmitter; refraining fromtransmitting the overall signal via said subsystem of the mobiletransmitter; and transmitting a plurality of components of the overallsignal via the plurality of transmitter chains thus transmitting theoverall signal.
 3. The communications method according to claim 2,wherein the limit is a bandwidth limit.
 4. The communications methodaccording to claim 2, wherein the subsystem of the mobile transmittercomprises an antenna and/or an element of the mobile transmitter otherthan the antenna.
 5. The communications method according to claim 1,wherein said overall signal comprises first and second frequencyintervals over which the overall signal comprises frequency content; andwherein the first and second frequency intervals are separatedtherebetween by a third frequency interval over which the overall signalis substantially devoid of frequency content.
 6. The communicationsmethod according to claim 5, wherein the first and second frequencyintervals comprise an aggregate bandwidth of 100 MHz; the firstfrequency interval comprises a bandwidth of 40 MHz; and the secondfrequency interval comprises a bandwidth of 60 MHz.
 7. Thecommunications method according to claim 1, wherein said first andsecond different components of the overall signal comprise respectivefirst and second different frequency content, respective first andsecond different bandwidths and/or respective first and second differentsubcarriers.
 8. The communications method according to claim 1, whereinsaid first transmitter chain of the plurality of transmitter chains andsaid second transmitter chain of the plurality of transmitter chainscomprise respective first and second different elements.
 9. Thecommunications method according to claim 8, wherein the respective firstand second different elements comprise respective first and seconddifferent antennas, respective first and second different poweramplifiers, respective first and second different Discrete FourierTransforms and/or respective first and second different Inverse DiscreteFourier transforms.
 10. The communications method according to claim 9,wherein said configuring a plurality of transmitter chains comprises:providing the mobile transmitter with the first and second antennas, thefirst and second power amplifiers, the first and second Discrete FourierTransforms and/or the first and second Inverse Discrete Fouriertransforms; and wherein said transmitting an overall signal by a mobiletransmitter by using a first transmitter chain of the plurality oftransmitter chains and a second transmitter chain of the plurality oftransmitter chains to transmit respective first and second differentcomponents of the overall signal over respective first and secondmutually exclusive frequencies comprises: transmitting the firstcomponent of the overall signal by using the first antenna, the firstpower amplifier, the first Discrete Fourier transform and/or the firstInverse Discrete Fourier Transform; and transmitting the secondcomponent of the overall signal by using the second antenna, the secondpower amplifier, the second Discrete Fourier transform and/or the secondInverse Discrete Fourier Transform.
 11. The communications methodaccording to claim 1, further comprising: forming a matrix; andprocessing the first and second different components of the overallsignal by using the matrix prior to transmitting said first and seconddifferent components of the overall signal by the mobile transmitter.12. The communications method according to claim 11, wherein forming amatrix comprises forming a product of first and second matrices; andwherein said processing the first and second different components of theoverall signal by using the matrix prior to transmitting said first andsecond different components of the overall signal by the mobiletransmitter comprises multiplying the first and second differentcomponents of the overall signal by the matrix.
 13. The communicationsmethod according to claim 1, wherein said configuring a plurality oftransmitter chains comprises: using an antenna by the first transmitterchain of the plurality of transmitter chains and also using the antennaby the second transmitter chain of the plurality of transmitter chains.14. A communications system comprising: a mobile transmitter thatcomprises a plurality of transmitter chains and a processor that isconfigured to perform operations comprising: transmitting an overallsignal by using a first transmitter chain of the plurality oftransmitter chains and a second transmitter chain of the plurality oftransmitter chains to transmit respective first and second differentcomponents of the overall signal over respective first and secondmutually exclusive frequencies.
 15. The communications system accordingto claim 14, wherein said operations further comprise: recognizing thatthe overall signal exceeds a limit associated with a subsystem of themobile transmitter; refraining from processing the overall signal bysaid subsystem of the transmitter; and processing a plurality ofcomponents of the overall signal by the plurality of transmitter chains.16. The communications system according to claim 15, wherein the limitis a bandwidth limit.
 17. The communications system according to claim15, wherein the subsystem of the mobile transmitter comprises an antennaand/or an element of the mobile transmitter other than the antenna. 18.The communications system according to claim 14, wherein said overallsignal comprises first and second frequency intervals over which theoverall signal comprises frequency content; and wherein the first andsecond frequency intervals are separated therebetween by a thirdfrequency interval over which the overall signal is substantially devoidof frequency content.
 19. The communications system according to claim18, wherein the first and second frequency intervals comprise anaggregate bandwidth of 100 MHz; the first frequency interval comprises abandwidth of 40 MHz; and the second frequency interval comprises abandwidth of 60 MHz.
 20. The communications system according to claim14, wherein said first and second different components of the overallsignal comprise respective first and second different frequency content,respective first and second different bandwidths and/or respective firstand second different subcarriers.
 21. The communications systemaccording to claim 14, wherein said first transmitter chain of theplurality of transmitter chains and said second transmitter chain of theplurality of transmitter chains comprise respective first and seconddifferent elements.
 22. The communications system according to claim 21,wherein the respective first and second different elements compriserespective first and second different antennas, respective first andsecond different power amplifiers, respective first and second differentDiscrete Fourier Transforms and/or respective first and second differentInverse Discrete Fourier transforms.
 23. The communications systemaccording to claim 22, wherein the operations further comprise:transmitting the first component of the overall signal by using thefirst antenna, the first power amplifier, the first Discrete Fouriertransform and/or the first Inverse Discrete Fourier Transform; andtransmitting the second component of the overall signal by using thesecond antenna, the second power amplifier, the second Discrete Fouriertransform and/or the second Inverse Discrete Fourier Transform.
 24. Thecommunications system according to claim 14, wherein the operationsfurther comprise: forming a matrix; and processing the first and seconddifferent components of the overall signal by using the matrix prior tosaid transmitting.
 25. The communications system according to claim 24,wherein said matrix comprises a product of first and second matrices.26. The communications system according to claim 14, wherein the firsttransmitter chain of the plurality of transmitter chains and the secondtransmitter chain of the plurality of transmitter chains share a commonantenna.
 27. The communications system according to claim 14, whereinsaid overall signal comprises first and second frequency intervals overwhich the overall signal comprises frequency content; the first andsecond frequency intervals are separated therebetween by a thirdfrequency interval over which the overall signal is substantially devoidof frequency content; and wherein the first and second frequencyintervals comprise an aggregate bandwidth of 100 MHz.
 28. Thecommunications system according to claim 27, wherein the first frequencyinterval comprises a bandwidth of 40 MHz.
 29. The communications systemaccording to claim 28, wherein the second frequency interval comprises abandwidth of 60 MHz.
 30. The communications system according to claim27, wherein the second frequency interval comprises a bandwidth of 60MHz.
 31. The communications system according to claim 30, wherein thefirst frequency interval comprises a bandwidth of 40 MHz.